The units and the maths
Everything a quotation can be denominated in, and the arithmetic for moving between units. None of it changes when the market does.
In order: the weight units cotton is traded in, converting a price between them, the fibre property tables, the yarn count systems and the converter, reading a fabric specification, the fabric weight maths, and turning a container rate into a cost per kilo. How yarn and polyester are made is on the next page.
The units everyone quotes in
Cotton is traded in four different weight units depending on the country. Nothing causes more silent mistakes than comparing two prices in two different units.
| Unit | Weight | Where you meet it |
|---|---|---|
| US statistical bale | 480 lb = 217.72 kg | What USDA and ICE volumes are counted in. |
| Indian bale | 170 kg | What Indian crop and arrival figures are counted in. |
| Pakistani bale | 155 kg | What PCGA arrival figures are counted in. |
| Candy | 355.62 kg (784 lb) | The Indian lint trading unit. Shankar-6 is quoted in rupees per candy. |
| Maund (Pakistan) | 40 kg | Seed cotton (phutti) in Pakistan is quoted in rupees per 40 kg maund. |
| Cotton futures contract | 50,000 lb (about 100 US bales) | The size of one ICE Cotton No. 2 contract. |
Rough shipping arithmetic: a 40 foot container carries about 19 to 21 tonnes of yarn depending on packing, so one container is roughly 55 to 60 candies of cotton spun and wound.
Converting a price between units
The three currencies of cotton conversation are US cents per pound, dollars per kilogram and rupees per candy. The bridges:
- Cents per pound to dollars per kilogram: multiply by 0.022046. So 90 c/lb is 1.98 $/kg.
- Dollars per kilogram to cents per pound: multiply by 45.359. So a 2.00 $/kg fibre is 90.7 c/lb.
- Rupees per candy to cents per pound: divide by the rupee rate to get dollars per candy, divide by 355.62 to get dollars per kilogram, then multiply by 45.359. Example, not a live price: Rs 69,100 per candy at 95.7 rupees to the dollar is 722 dollars per candy, which is 2.03 $/kg, which is about 92 c/lb.
- Yarn conversion cost check: a cotton yarn price minus the cost of its fibre (allow 8 to 15 percent spinning waste depending on carded or combed) is the mill's conversion charge plus margin. Comparing that spread across quotes tells you more than comparing the headline prices.
Natural fibre properties
What each fibre can and cannot do, and why. Almost every argument about quality on a finished garment traces back to one of the columns below.
| Fibre | Staple length | Fineness | Tenacity dry cN/tex | Strength when wet | Elongation per cent | Moisture regain per cent | Density g/cm³ | Behaviour in heat |
|---|---|---|---|---|---|---|---|---|
| Cotton, upland Seed, cellulose | 22 to 32 mm | 3.5 to 4.9 micronaire | 26 to 44 | Gains 5 to 15 per cent | 5 to 10 | 7 to 8.5 | 1.52 to 1.55 | No melting point. Scorches from about 150 C, burns. |
| Cotton, extra long staple Seed, cellulose | 34 to 40 mm | 3.4 to 4.2 micronaire | 35 to 45 | Gains 5 to 15 per cent | 5 to 9 | 7 to 8.5 | 1.52 to 1.55 | As upland. |
| Wool, merino Animal, protein | 55 to 100 mm | 17 to 23 micron | 10 to 15 | Loses 10 to 25 per cent | 25 to 45 | 14 to 18 | 1.30 to 1.32 | No melting point. Chars and self extinguishes. |
| Cashmere Animal, protein | 30 to 50 mm | 14 to 19 micron | 10 to 14 | Loses 10 to 25 per cent | 30 to 40 | 15 to 17 | About 1.30 | As wool. |
| Silk, mulberry Animal, filament protein | Continuous filament | 1.0 to 1.5 denier per filament | 35 to 50 | Loses 15 to 20 per cent | 15 to 25 | 10 to 11 | 1.33 to 1.35 | No melting point. Degrades from about 170 C. |
| Flax, linen Bast, cellulose | 25 to 150 mm as spun | 12 to 25 micron | 45 to 70 | Gains 10 to 20 per cent | 1.5 to 3 | 10 to 12 | 1.50 to 1.54 | No melting point. As cotton. |
| Hemp Bast, cellulose | 15 to 50 mm as spun | 16 to 50 micron | 50 to 70 | Gains 10 to 20 per cent | 1.5 to 3 | 8 to 12 | About 1.48 | As flax. |
| Ramie Bast, cellulose | 40 to 150 mm as spun | 20 to 40 micron | 50 to 75 | Gains 10 to 25 per cent | 2 to 4 | 8 to 9 | 1.51 to 1.55 | As flax. |
| Jute Bast, cellulose and lignin | 1.5 to 4 mm ultimate | 15 to 25 micron | 30 to 45 | Roughly unchanged | 1.5 to 2 | 12 to 14 | 1.44 to 1.50 | No melting point. Chars. |
These are typical published ranges compiled by VeriMills for orientation. They are not a specification and they do not replace a test report. Tenacity is measured dry at 20 C and 65 per cent relative humidity, in centinewtons per tex, which is the unit a spinner will quote. Ranges are given as ranges on purpose: a single figure for the strength of cotton would be false precision, because it moves with variety, season, ginning and test method.
What each column is really telling you
- Tenacity sets how fine a count the fibre can be spun to and how the yarn survives weaving. It is the reason 80s cotton needs extra long staple and 80s jute does not exist at all.
- Elongation decides creasing and recovery. Wool at 25 to 45 per cent springs back; linen at 1.5 to 3 per cent cannot, and no finish will make it.
- Moisture regain decides comfort, dyeing behaviour and, as below, what you actually pay for.
- Strength when wet decides what survives laundering. The cellulosics gain, the proteins lose, and that single difference explains most care labels.
| Cotton, upland | The bulk of world trade. Micronaire is a fineness and maturity reading combined, which is why it is a range and not a diameter. |
|---|---|
| Cotton, extra long staple | Giza, Pima, Suvin and similar. The longer staple is what makes counts above 60s practical. |
| Wool, merino | Weak in tenacity but very extensible, which is why wool fabrics recover their shape and cotton ones crease. |
| Cashmere | Priced on micron and length together. Adulteration with fine wool or yak is common enough that a fibre identification test is normal practice. |
| Silk, mulberry | Quoted in denier, not count, because it is reeled rather than spun. |
| Flax, linen | Very strong and very inextensible, which is exactly why linen creases and will not recover. |
| Hemp | Behaves like a coarser flax. Softness depends almost entirely on how far the degumming was taken. |
| Ramie | The strongest of the common naturals, and the stiffest. Usually blended rather than used alone. |
| Jute | The lignin is what yellows it in sunlight and what limits how fine it can be spun. |
What this means for the natural fibre properties
What this is Typical published property ranges for the natural fibres a garment buyer actually meets, compiled by VeriMills from standard textile reference literature.
How to read it Each row is one fibre and each column one measurable property, most given as a range from typical low to typical high rather than one figure. Tenacity is strength for the fibre's thickness, so higher spins finer and stronger; elongation is how far it stretches before breaking, so higher creases less; moisture regain is how much water it holds from ordinary air; and the wet strength column says what washing does to it. Compare fibres DOWN a column, never across a row, and the notes table underneath gives one plain fact per fibre.
What moves it Nothing quickly. These are properties of the fibre itself. What does move within the ranges is the crop: variety, growing season, rainfall and ginning all shift cotton within its band from year to year.
How to use it Framing a question before you specify. From roughly 60s upward a mill starts asking for extra long staple, and by 80s it is not optional. This table is why, and why the price step that comes with it is not negotiable.
The trap These are ranges, not a specification, and they do not replace a test report. Do not quote a number from here into a contract.
Take it with you the natural fibre table: the table as a spreadsheet , with its sources, its licence and a sheet explaining every column inside the file.
Man-made fibre properties
Synthetics and regenerated cellulosics, side by side on the same measures. The column to read first is what happens when the fibre gets wet.
| Fibre | Tenacity dry cN/tex | Strength when wet | Elongation per cent | Moisture regain per cent | Density g/cm³ | Behaviour in heat |
|---|---|---|---|---|---|---|
| Polyester, PET Synthetic, melt spun | 35 to 60 | Essentially unchanged | 15 to 45 | 0.4 | About 1.38 | Melts 250 to 260 C. Softens from about 230 C. |
| Nylon 6 Synthetic, melt spun | 40 to 60 | Loses 10 to 15 per cent | 20 to 40 | 3.5 to 4.5 | About 1.14 | Melts 215 to 220 C. |
| Nylon 6.6 Synthetic, melt spun | 40 to 65 | Loses 10 to 15 per cent | 16 to 40 | 4 to 4.5 | About 1.14 | Melts 250 to 260 C. |
| Acrylic Synthetic, solvent spun | 20 to 30 | Loses 0 to 20 per cent | 25 to 50 | 1.5 to 2 | 1.16 to 1.18 | No true melting point. Softens 220 to 250 C. |
| Viscose rayon Regenerated cellulose | 20 to 27 | Loses 40 to 55 per cent | 15 to 30 | 11 to 13 | 1.50 to 1.52 | No melting point. Chars, as cotton. |
| Modal Regenerated cellulose | 30 to 40 | Loses 30 to 45 per cent | 10 to 15 | 11 to 13 | About 1.50 | As viscose. |
| Lyocell Regenerated cellulose | 40 to 45 | Loses 10 to 20 per cent | 12 to 16 | 11 to 13 | About 1.50 | As viscose. |
| Acetate Cellulose ester | 10 to 14 | Loses 30 to 40 per cent | 25 to 45 | 6 to 6.5 | About 1.32 | Softens 200 to 230 C. Dissolves in acetone. |
| Polypropylene Synthetic, melt spun | 40 to 70 | Unchanged | 15 to 35 | Under 0.1 | 0.90 to 0.91 | Melts 160 to 175 C. |
| Elastane, spandex Segmented polyurethane | 6 to 9 | Roughly unchanged | 400 to 700 | 0.75 to 1.3 | 1.15 to 1.32 | Softens 175 to 200 C. Degrades above about 230 C. |
These are typical published ranges compiled by VeriMills for orientation. They are not a specification and they do not replace a test report. Man-made fibres are engineered to a target, so a producer can move a grade well outside these bands on purpose. High tenacity polyester and nylon are made deliberately stronger; low pill acrylic is made deliberately weaker. Always take the producer's own data sheet for the exact grade you are buying.
| Polyester, PET | High tenacity industrial grades reach 60 to 80. The near zero regain is why polyester dries fast and why it holds static. |
|---|---|
| Nylon 6 | The lower melting point matters in finishing and in heat transfer printing. Do not assume a nylon setting works on both types. |
| Nylon 6.6 | Tougher and more heat resistant than nylon 6, and dearer. Abrasion resistance is the best of the common fibres. |
| Acrylic | Bulked to imitate wool. Weak, but warm for its weight and very light fast, which is why it dominates outdoor knitwear. |
| Viscose rayon | The wet strength loss is the single most important number on this page. A viscose garment is at its weakest in the wash, which is where seam failures and distortion come from. |
| Modal | A high wet modulus viscose. Better wet behaviour than standard viscose but still well short of cotton. |
| Lyocell | The strongest of the cellulosics wet and dry. Fibrillates, which is a fault on a plain fabric and the desired effect on a peached one. |
| Acetate | Weak. Used for linings and drape rather than for wear. The acetone sensitivity catches out spot cleaning. |
| Polypropylene | The only common fibre lighter than water, so it covers more area per kilo than anything else. The low melting point rules out most conventional dyeing and pressing. |
| Elastane, spandex | Never used alone. Two to five per cent of the weight changes the whole behaviour of a fabric, and it is the component that fails first under chlorine, heat and time. |
Moisture allowance: weight you pay for
Fibre absorbs water from the air, so a bale weighs more in a humid warehouse than a dry one. The trade settles this by agreeing a fixed allowance per fibre and invoicing on conditioned weight, which is the bone dry weight plus that allowance. These are agreed conventions rather than measurements, and they differ from the measured regain in the tables above.
The figures below are not a rule of thumb. Every one of them is taken from Annex IX of Regulation (EU) No 1007/2011 (opens in a new tab), the European law on textile fibre names and labelling, which is why the same numbers turn up in contracts far outside Europe. Note where one fibre has two rows. Mercerised cotton is settled at a different figure from ordinary cotton, combed wool from carded, nylon staple from nylon filament. Those pairs are where the money is, and naming the wrong one of a pair is not a rounding argument.
| Fibre | Allowance, per cent |
|---|---|
| Cotton, normal fibres | 8.5 |
| Cotton, mercerised fibres | 10.5 |
| Wool and animal hair, combed | 18.25 |
| Wool and animal hair, carded | 17.0 |
| Silk | 11.0 |
| Flax | 12.0 |
| True hemp | 12.0 |
| Jute | 17.0 |
| Ramie, bleached fibre | 8.5 |
| Viscose | 13.0 |
| Modal | 13.0 |
| Lyocell | 13.0 |
| Cupro | 13.0 |
| Acetate | 9.0 |
| Triacetate | 7.0 |
| Polyamide or nylon, staple | 6.25 |
| Polyamide or nylon, filament | 5.75 |
| Polyester | 1.5 |
| Acrylic | 2.0 |
| Modacrylic | 2.0 |
| Polypropylene | 2.0 |
| Elastane | 1.5 |
On a 20 tonne cotton order the 8.5 per cent allowance is roughly 1.7 tonnes of agreed water, so it is not a footnote. Two practical consequences. A polyester and cotton blend settles somewhere between 1.5 and 8.5 depending on the ratio, and the ratio therefore needs stating on the contract. And a shipment that has sat in a wet port can arrive above its conditioned weight, which is what a conditioning test at destination is for. These are typical published ranges compiled by VeriMills for orientation. They are not a specification and they do not replace a test report. Confirm the allowance your own contract actually names. These are the statutory European figures, which is the nearest thing to a universal rule that exists, but a contract can still write its own.
Source. Annex IX of Regulation (EU) No 1007/2011 of the European Parliament and of the Council on textile fibre names and related labelling, reproduced under Commission Decision 2011/833/EU, which allows reuse with the source acknowledged. Only the text published on EUR-Lex (opens in a new tab) is authentic. The annex lists further fibres we have left out because a cotton, yarn or garment buyer will not meet them: kapok, abaca, coir, sisal, alginate, aramid, elastodiene, glass fibre, melamine, paper yarn and polyacrylate.
What this means for the man-made fibre properties
What this is Typical published property ranges for synthetic and regenerated cellulosic fibres, compiled by VeriMills, plus the commercial regain allowances weight is settled on, which are the statutory figures from Annex IX of Regulation (EU) No 1007/2011.
How to read it The property table reads like the natural fibre one: each row a fibre, each column a measure, ranges rather than single figures, compared down a column. The allowance table below it is a different kind of number altogether: not a measurement but the agreed percentage of water weight added onto bone dry weight when a delivery is invoiced, fibre by fibre. Where one fibre appears twice, such as cotton and mercerised cotton, the contract has to name which row applies, because the two settle at different weights.
What moves it Nothing in the fibre. The allowances change only when the regulation itself is amended, which is rare, or when a contract writes its own.
How to use it Predicting how a blend will behave before you sample it, and checking that a quotation's weight basis matches the fibre it is quoting.
The trap Producers engineer grades well outside these bands deliberately, so take the actual grade's data sheet for anything that matters. Viscose losing roughly half its strength wet is the one number on this page that most often explains a quality complaint.
Take it with you the man-made fibre table: the table as a spreadsheet , with its sources, its licence and a sheet explaining every column inside the file.
Take it with you the commercial regain allowances: the table as a spreadsheet , with its sources, its licence and a sheet explaining every column inside the file.
Yarn count (thickness) systems
A yarn count states how fine the yarn is. Two families exist: indirect counts, where a bigger number means a finer yarn, and direct counts, where a bigger number means a coarser one.
| System | Definition | Direction | Where you meet it |
|---|---|---|---|
| Ne (English count) | Hanks of 840 yards per pound | Higher = finer | The number on almost every cotton yarn quote: 20s, 30s, 40s. |
| Nm (metric count) | Metres per gram | Higher = finer | Common in Europe and for wool and blends. |
| Tex | Grams per 1,000 metres | Higher = coarser | The scientific unit; easiest for arithmetic. |
| Denier | Grams per 9,000 metres | Higher = coarser | Used for filament yarns: polyester, nylon, viscose filament. |
The bridges: Ne × tex = 590.5 · Nm × tex = 1000 · denier = 9 × tex. So a 30s Ne yarn is 19.7 tex, which is Nm 50.8, which is 177 denier. Every other pair of systems, and the ply notation that catches people out, is in the count converter below.
Converting a yarn count into any other
Every count system is a different way of saying the same thing: how much yarn you get for a given weight, or how much a given length weighs. Once you can get to tex, you can get to anything.
| From, down. To, across. | Ne | Nf | Nm | Wor | Lea | Tex | Den |
|---|---|---|---|---|---|---|---|
| English cotton (Ne) hanks of 840 yd per lb | same | × 0.8467 | × 1.6934 | × 1.5 | × 2.8 | 590.5 ÷ n | 5314.9 ÷ n |
| French (Nf) hanks of 1000 m per 0.5 kg | × 1.1811 | same | × 2 | × 1.7716 | × 3.307 | 500 ÷ n | 4500 ÷ n |
| Metric (Nm) metres per gram | × 0.5905 | × 0.5 | same | × 0.8858 | × 1.6535 | 1000 ÷ n | 9000 ÷ n |
| Worsted hanks of 560 yd per lb | × 0.6667 | × 0.5645 | × 1.1289 | same | × 1.8667 | 885.8 ÷ n | 7972.3 ÷ n |
| Linen, wet spun leas of 300 yd per lb | × 0.3571 | × 0.3024 | × 0.6048 | × 0.5357 | same | 1653.5 ÷ n | 14881.6 ÷ n |
| Tex grams per 1000 m | 590.5 ÷ n | 500 ÷ n | 1000 ÷ n | 885.8 ÷ n | 1653.5 ÷ n | same | × 9 |
| Denier grams per 9000 m | 5314.9 ÷ n | 4500 ÷ n | 9000 ÷ n | 7972.3 ÷ n | 14881.6 ÷ n | ÷ 9 | same |
n is the count you are starting from. Where the cell reads a number divided by n, divide; where it reads times a number, multiply. The whole table is generated from six definitions, so there is nothing here to mistype: Ne is hanks of 840 yards per pound, Nf hanks of 1000 metres per half kilo, Nm metres per gram, worsted hanks of 560 yards per pound, linen leas of 300 yards per pound, and denier grams per 9000 metres.
The counts we collect, in every system
| Cotton count | Tex | Nm | Denier | Worsted |
|---|---|---|---|---|
| 10s Ne | 59.1 | 16.9 | 531 | 15.0 |
| 20s Ne | 29.5 | 33.9 | 266 | 30.0 |
| 30s Ne | 19.7 | 50.8 | 177 | 45.0 |
| 40s Ne | 14.8 | 67.7 | 133 | 60.0 |
| 60s Ne | 9.8 | 101.6 | 89 | 90.0 |
| 80s Ne | 7.4 | 135.5 | 66 | 120.0 |
Filament, which is quoted the other way round
| Specification | Tex | Dtex | Nm | Ne equivalent | Denier per filament |
|---|---|---|---|---|---|
| 75d/36 | 8.3 | 83 | 120.0 | 70.9 | 2.08 |
| 150d/48 | 16.7 | 167 | 60.0 | 35.4 | 3.13 |
In 150d/48 the first number is the denier of the whole yarn and the second is how many filaments share it, so denier per filament is the first divided by the second. That second number is what decides the handle: the same 150 denier split across 48 filaments is a very different fabric from 150 split across 144. The Ne equivalent is arithmetic only, offered so you can compare a filament against a spun count; nobody quotes filament in Ne.
Ply: easy to misread, worth an email
Plying two yarns together makes a yarn twice as heavy for its length, so the resultant count is half the singles count in any indirect system, and double in any direct one. Two 40s singles plied give a resultant 20s. In tex, two 14.8 tex singles give 29.5 tex.
The trouble is the notation. 2/40s in the English cotton trade normally means two 40s singles, resultant 20s. Written 40/2 it usually means the same thing. But some mills, and much of the worsted trade, use the same marks to state the resultant count, in which case the singles are 80s. The two readings differ by a factor of four in fabric weight, which is not a rounding error.
There is no convention that settles it, so do not try to infer it. Ask the mill to state the singles count and the resultant count separately, in writing, on the order. It takes one line and it removes the single most common cause of a fabric coming in at the wrong weight.
What this means for the count conversions
What this is Conversion rules between the seven yarn count systems, generated from the definition of each system rather than transcribed, plus the counts on our own reference sheet worked out in all of them.
How to read it In the conversion tables each row is one yarn and each column shows that same yarn's number in a different counting system. The systems run in opposite directions: cotton count, Nm and worsted are indirect, so a HIGHER number is a FINER yarn, while tex, dtex and denier weigh the yarn, so there a higher number is a thicker one. In a filament spec like 150d/48, the first figure is the denier of the whole yarn and the second is how many strands share it, so the per-filament fineness is the first divided by the second.
What moves it Nothing. These are definitions, not measurements, so they do not change and never go out of date.
How to use it Comparing quotations that arrive in different systems, which is the normal case when you are asking Pakistan, India, China and Turkey for the same yarn.
The trap Ply notation. 2/40s almost always means two 40s singles giving a resultant 20s, but it is sometimes used to state the resultant instead, and the two readings differ twofold in fabric weight. The systems also measure slightly different things in practice: a nominal count is what the yarn was meant to be, and the actual count on test can differ by a percent or two.
Take it with you the conversion rules and a converter you can type into: the table as a spreadsheet a calculator with live formulas , with its sources, its licence and a sheet explaining every column inside the file.
Reading a fabric specification
A woven fabric spec like 20 × 16 / 128 × 60, 63", 3/1 twill reads as: warp yarn count 20s, weft yarn count 16s, 128 warp ends per inch, 60 weft picks per inch, 63 inches wide, woven in a three up one down twill. Higher counts mean finer yarns; more ends and picks mean a denser cloth. Together with the weave, those four numbers fix the weight and most of the price of the greige fabric.
Knitted fabric is specified differently: by yarn count, machine gauge, stitch construction (single jersey, pique, interlock, rib, fleece) and finished GSM, grams per square metre. A typical T-shirt jersey runs 140 to 180 GSM; a hoodie fleece 280 to 350. GSM is the number to hold constant when comparing two knit quotes.
The main weaves to know: plain (over one, under one; poplin and sheeting), twill (the diagonal line; denim, chino, workwear), and satin (long floats, smooth face; dress and lining cloths). Everything fancier is a variation on these three.
Those four numbers do not only describe the cloth, they determine what it weighs. The arithmetic, worked through a poplin, a twill, a denim and a jersey, is in fabric weight maths below.
Fabric weight, and the yarn it needs
A construction is a weight in disguise. Two counts and two densities are enough to tell you the grams per square metre before a single metre is woven, and from there how much yarn the order needs.
The rule
| Grams per square metre | 23.25 × [ EPI × (1 + warp allowance) ÷ Ne warp + PPI × (1 + weft allowance) ÷ Ne weft ] |
|---|---|
| EPI and PPI | Ends per inch, meaning threads running the length of the roll, and picks per inch, meaning threads running across it. Together they are the density. |
| Where 23.25 comes from | One metre of width holds EPI × 39.37 ends. One metre of a 1s Ne yarn weighs 453.6 × 1.0936 ÷ 840 = 0.5905 g. Multiply the two and you get 23.249. It is arithmetic, not a fudge factor. |
| Ounces per square yard | GSM ÷ 33.906. Going back the other way, ounces × 33.906. |
| Yarn per metre of fabric | 0.5905 × width in inches × [ EPI × (1 + allowance) ÷ Ne warp + PPI × (1 + allowance) ÷ Ne weft ], in grams. Metres per kilo is 1000 divided by that. |
The allowances are the soft part. Crimp is the extra yarn length taken up by weaving over and under, and it varies with weave, tension and the loom. The 10 per cent warp and 5 per cent weft used below are ordinary planning allowances, not a specification, and not a promise. On a real order the mill measures crimp on its own machines and the answer can move several per cent either way. Treat the output as a budgeting figure and confirm the weight on a sealed sample.
Three woven constructions, worked
| Fabric | Construction | Warp g/m² | Weft g/m² | GSM | oz/yd² | g per metre | m per kg |
|---|---|---|---|---|---|---|---|
| Poplin 1 over 1 plain | 40s × 40s 133 × 72, 57 in | 85.0 | 43.9 | 129 | 3.80 | 187 | 5.36 |
| Twill 3 over 1 | 20s × 20s 108 × 56, 63 in | 138.1 | 68.4 | 206 | 6.09 | 330 | 3.03 |
| Denim 3 over 1 | 10s × 10s 72 × 52, 63 in | 184.1 | 126.9 | 311 | 9.17 | 498 | 2.01 |
- Poplin. A standard fine shirting. Both directions the same count, so the difference between the two lines is density alone. Of the 187 grams a metre needs, 123 g is warp and 64 g is weft, so a 10,000 metre order needs roughly 1,231 kg of 40s for the warp and 636 kg of 40s for the weft, before dyeing and finishing losses.
- Twill. A workwear and chino weight. Halving the count from 40s to 20s doubles the contribution of every thread. Of the 330 grams a metre needs, 221 g is warp and 109 g is weft, so a 10,000 metre order needs roughly 2,210 kg of 20s for the warp and 1,094 kg of 20s for the weft, before dyeing and finishing losses.
- Denim. Around nine ounces, which is a light to middle denim. Heavier denims use counts coarser than anything on our sheet, and most modern denim adds elastane, which this calculation does not account for. Of the 498 grams a metre needs, 295 g is warp and 203 g is weft, so a 10,000 metre order needs roughly 2,947 kg of 10s for the warp and 2,031 kg of 10s for the weft, before dyeing and finishing losses.
A knit, which is calculated backwards
You cannot predict a knit weight from the count alone, because the loop length decides it and the loop length is a machine setting. So a knit is specified by its finished weight and the arithmetic runs the other way: from the weight you know, to the yarn the order will consume.
| Fabric | Single jersey, 30s cotton, 160 g/m² finished, 72 in open width |
|---|---|
| Grams per metre of fabric | 160 ÷ 39.37 × 72 = 292.6 g |
| Adding 15 per cent process loss | 292.6 × 1.15 = 336.5 g |
| Metres per kilo of yarn | 1000 ÷ 336.5 = 2.97 m |
| In ounces | 160 ÷ 33.906 = 4.72 oz/yd² |
The 15 per cent covers knitting waste, dyeing loss and inspection cuts together. It is a planning allowance in exactly the way the crimp figures above are, and a well run mill on a long run will beat it while a short run of a difficult shade will not. Ask for the mill's own figure and use theirs.
If you do have the machine settings, the weight follows from them: GSM = courses per cm × wales per cm × stitch length in mm × tex ÷ 100. That is the same physics as the woven formula, counting loops instead of crossings.
Grams and ounces, side by side
| g/m² | 110 | 130 | 160 | 180 | 200 | 240 | 280 | 320 | 360 |
|---|---|---|---|---|---|---|---|---|---|
| oz/yd² | 3.24 | 3.83 | 4.72 | 5.31 | 5.90 | 7.08 | 8.26 | 9.44 | 10.62 |
Two traps worth knowing. An ounce per square yard is not an ounce per linear yard, and denim is quoted in the first while some suppliers casually quote the second, which at a 63 inch width is nearly twice the number. And a weight quoted greige is not the weight quoted finished: shrinking, singeing, mercerising and resin all move it, usually upward on the square metre because the cloth pulls in. Always ask which state a weight refers to.
What this means for the fabric weight calculations
What this is The standard relationship between a woven construction and its weight, the same thing for a knit worked backwards from finished weight, and the yarn each consumes per metre of cloth.
How to read it The woven table works forwards: each row is a named construction, its counts and threads per inch shown under the name, and the columns are what those produce, with the bold GSM the headline answer and the last two columns the yarn one metre of that cloth consumes. The knit table runs the other way, from a finished weight back to yarn consumption, one row per step of the arithmetic with the formula written out in the row. The strip at the bottom is a straight equivalence scale between grams per square metre and ounces per square yard.
What moves it Nothing in the formula. What moves is the allowance you feed it: crimp depends on the weave and the loom, process loss on the mill and the shade.
How to use it Sanity checking a quotation before you accept it. If a mill quotes a construction and a weight that the formula cannot reconcile, one of the two numbers is wrong and it is worth finding out which before the order is placed.
The trap The allowances are planning figures, not specifications. So is the result. A calculated GSM tells you what to expect and what to argue about; only a sealed sample and a test report tell you what you are buying. Greige weight and finished weight are different numbers for the same cloth.
Take it with you the worked examples and a calculator with live formulas: the table as a spreadsheet a calculator with live formulas , with its sources, its licence and a sheet explaining every column inside the file.
Turning a container rate into a cost per kilo
Freight is quoted per box and costed per kilo, and the conversion is where landed cost calculations usually go wrong. The arithmetic itself is trivial: the ocean rate divided by the kilograms you actually load, times one hundred, gives you cents per kilogram.
The part that is not trivial is the second number. A forty foot high cube can legally carry roughly twenty six tonnes, and apparel almost never reaches that. Garments cube out long before they weigh out, so a realistic net load is eight tonnes for bulky knitwear and jackets, around twelve for typical mixed apparel, and eighteen or more only for dense, well compressed goods or for yarn. Using the weight limit instead of the real load will understate your freight per kilo by a factor of two or three.
A worked example, with round numbers chosen so they are obviously not a quote. A three thousand dollar rate on a container holding twelve tonnes net is 3000 ÷ 12000 × 100, which is 25 cents per kilogram. The same rate on a bulky load of eight tonnes is 37.5 cents. That twelve and a half cent difference is larger than most of the margin arguments people have about the yarn price.
And the sea leg is only part of it. Origin handling, destination terminal charges, customs duty, insurance and inland movement are all lane specific, and on a cheap freight week they add up to more than the ocean rate itself. This is the whole reason an FOB quote and a CFR quote cannot be compared until the freight is stripped out of the second one.
The ready reckoner on the market page does the division for six rates against three loading assumptions. It contains no market data at all, only arithmetic, so it can never be out of date. Read your actual lane rate at Drewry or Freightos, both linked there.