How to Read Fabric Construction

Reading the notation

Buyers sometimes reverse warp and weft, or treat all four numbers as yarn counts. The rule to hold: counts before the slash, density after it.

The worked example above is a poplin construction — for more worked examples, see the commonly requested poplin counts and constructions, or the finer end of the same discipline in cambric constructions and their end uses.

What an end and a pick actually are

An end is a single warp thread — one thread running the length of the fabric, parallel to the selvedge. A pick is a single weft thread — one insertion of yarn across the width of the loom. Each pass of the weft is one pick, which is why weft density is quoted in picks per inch (PPI) and warp density in ends per inch (EPI).

So in 40×40/120×60, the cloth carries 120 ends and 60 picks in every inch — 180 threads per square inch in total. That combined figure is roughly what retail bedding markets as "thread count". A trade construction doesn't add the two into one figure — warp and weft do different jobs in the cloth and are specified, woven and costed separately.

"Fabric count" (or cloth count) is simply the two density figures read together — 120×60. If a supplier quotes per centimetre rather than per inch, divide the inch figures by 2.54: 120×60 per inch is approximately 47×24 per cm. Same cloth, different unit — always confirm which unit a quotation uses before comparing two constructions.

What the number does not tell you

The biggest misunderstanding is that a construction is a complete specification. It isn't. 40×40/120×60 does not, by itself, tell you:

• Exact finished GSM, or the finished and usable width
• Composition, weave, and whether the yarn is carded, combed or compact
• Yarn quality, sizing level, and finished hand feel
• Shrinkage, colourfastness, dyeing method and printing suitability
• Whether the fabric will match your reference in look or performance

And "higher" isn't automatically "better." A higher density can add coverage and body, but it also changes hand, weight and processing behaviour. The density must suit the product, not just be large.

Weight: GSM, ounces, and converting between them

Construction cannot be converted into a weight, but weight units can be converted into each other — and that is where a lot of avoidable confusion sits, because European and Pakistani buyers work in GSM (grams per square metre) while American and denim buyers work in ounces per square yard. The factor is exact and worth memorising:

1 oz/yd² = 33.906 GSM. So multiply ounces by 33.906 to get GSM, or divide GSM by 33.906 to get ounces. A 10 oz denim is ≈ 339 GSM; a 200 GSM jersey is ≈ 5.9 oz.

Two cautions. First, these are bands, not definitions — they overlap, and finishing moves the finished figure in both directions. Second, a target GSM is an outcome of construction, yarn, weave and finishing, not an independent input you can set alongside a construction and expect both to be met exactly. Where the two conflict, one of them has to give, and it is better to decide which in the brief than in bulk.

The arithmetic does, however, run one way. You cannot set a construction and a finished GSM independently and expect both to be met — but you can estimate what a given construction ought to weigh in the loom state, and use that to catch a specification that does not add up before you have paid for sampling:

GSM ≈ (EPI ÷ warp count + PPI ÷ weft count) × 25.6

Worked on the 20 × 24 / 60 × 60 from the top of this page: (60 ÷ 20 + 60 ÷ 24) × 25.6 = 5.5 × 25.6 ≈ 141 GSM — the medium-weight utility cloth that construction implies, not a fine shirting and not a canvas.

The constant is where most published versions of this formula go wrong. Derived from first principles — 39.37 inches per metre, 1.0936 yards per metre, 453.59 grams per pound, 840 yards per hank of Ne 1 — the no-crimp figure is 23.25. The 25.6 in common circulation already carries roughly ten per cent for crimp. So a spec sheet that applies 25.6 and then adds "a few per cent for crimp" has counted it twice. Use 25.6 and stop, or use 23.25 and add your own allowance — never both.

Treat the output as what it is: an estimate of the greige weight implied by the construction alone. It does not predict the finished GSM, because desizing and scouring remove weight while shrinkage concentrates it, and the two do not cancel to a fixed percentage. The finished figure is confirmed on an approved sample, not calculated.

One place the number has a hard commercial edge: our dyeing minimum steps at 160 GSM — 1,500m per colour below it, 3,000m per colour at and above it. That line runs straight through the typical t-shirt jersey band, so on knits a target GSM is a commercial decision as much as a handfeel one.

See low-MOQ fabric sourcing from Pakistan for the confirmed minimums each weight band falls under.

The one thing to remember

A construction describes how the fabric is built, not completely how the finished fabric will look, feel or perform. It should narrow a development — never replace physical approval. Always support it with composition, weave, target GSM, finished width, finish, end use and an approved physical reference.

Buyer checklist

Before you send us a construction, know where the numbers came from — a lab analysis, a supplier spec sheet, a competitor quote, a physical fabric, an estimate, or just a market name. Then confirm on the finished cloth:

• Finished GSM and finished width
• Weave and composition
• Shrinkage and hand feel
• Colour and print performance
• An approved physical sample, plus any test requirements

How to count picks on a physical fabric

If you have the cloth but no spec sheet, you can establish the count yourself. The tool is a pick glass — also sold as a counting glass or linen tester — a folding magnifier with a fixed measuring window, most commonly one inch.

• Lay the fabric flat and without tension.
• Identify the warp: threads running parallel to the selvedge are ends; the threads crossing them are picks.
• Keep the glass well clear of the selvedge — it is constructed differently and is not representative of the body of the cloth.
• Count ends across one inch measured along the width, and picks across one inch measured along the length, using a needle to keep your place.
• Repeat in several places along both the width and the length and average.

The state of the cloth changes the answer. Fabric usually contracts in width during wet processing and finishing, so a finished cloth will generally show more ends per inch than the same cloth measured in loom state. When your count doesn't reconcile with a quoted construction, first confirm whether the quote was on-loom or finished — that gap is a specification question for the supplier, not a rounding error.

If you'd rather not count threads under a pick glass, send us a cutting. A physical reference plus the end use tells us more than a construction written on paper — and it's how we'd start a development anyway.

Why two identical constructions differ

Two suppliers can both quote 40×40/120×60 and still deliver different fabrics — because of cotton quality and staple length, yarn evenness and strength (CSP), carded vs combed yarn, actual vs nominal loom density, crimp, loom type, sizing, grey and finished width, the desizing/scouring/bleaching route, mercerisation, sanforisation, calendering, softener or resin, dyeing method, even moisture content at testing. Same notation, different cloth.

How to identify good cotton fabric

"Good cotton" is not one property. Quality is set at three levels — fibre, yarn and cloth — and a construction like 40×40/120×60 only fixes part of the third. Two fabrics with identical constructions can sit at opposite ends of the quality range. Here is what to check at each level, and which checks you can run yourself before anything reaches a lab.

Fibre and yarn: what to ask for, not what to look for. You cannot see staple length or spinning route in finished cloth, so these belong on the spec sheet, not in your hands. Ask three questions. First, is the yarn carded, combed or compact? Combing removes short fibres before spinning, so combed yarn runs smoother and stronger with fewer neps — the small white specks you see on lower-grade or carded cloth. Second, what is the actual yarn count, warp and weft — not the nominal one on the quotation? Third, longer-staple cotton spins into finer, more even yarn; if evenness matters for your product, ask the supplier to state the staple and the yarn's Uster evenness (CV%) — CSP is a strength figure, not an evenness figure — rather than accepting "good quality cotton" as a description.

Six checks you can run on a swatch

• Hold it to light. Density should be even edge to edge — no thick-and-thin bands, no missed picks, no reediness in the warp.
• Read the surface. Count the neps and slubs across a hand-span. A scattering is normal in carded qualities; heavy speckling signals short fibre or poor cleaning.
• Test the hand. Crush the cloth in your fist and release. Body that comes from construction springs back; stiffness that comes from sizing or starch stays creased and will wash out, taking the "quality" feel with it.
• Weigh it. Cut a measured 10 cm × 10 cm square, weigh it in grams and multiply by 100 for GSM. Compare against the stated figure — GSM is always approx., but the gap should be explainable.
• Wash it once. Mark a square before washing, re-measure after, and rub a dry white cloth across any dyed area. Compare shrinkage and staining against the tolerance in your own spec, not a general rule.
• Burn a snippet. 100% cotton burns steadily, smells of burning paper and leaves a soft grey ash; synthetics melt into a hard bead. This only rules out a significant synthetic content — it cannot separate cotton from other cellulosics such as viscose or linen, which burn the same way, and it says nothing about staple, spinning or weaving quality. Fibre composition is confirmed by lab test, not by flame.

What still needs a lab

Shrinkage to a standard wash method, colourfastness ratings, tensile and tear strength, and pilling are lab numbers. For bulk orders, agree the test requirements at development stage and confirm them against the approved sample — a swatch check narrows the field; it does not replace testing. Our catalogue runs to 1,583 qualities across greige, dyed, RFD and print bases. Happy to send physical swatches — no obligation.

Related knowledge

• How to verify a fabric supplier in Pakistan

  Reading the spec is half the job — the other half is checking that the supplier quoting it can actually deliver it.

• Cotton poplin: construction, GSM and sourcing

  The constructions used as examples above, in the context of one real fabric family.

• What a greige fabric specification must state

  This page teaches how to read the notation; that one is what to state around it on an order.

• Metres or kilograms: how greige is measured and invoiced

  GSM as a commercial quantity — the conversion between weight and length bases, and what the contract states.

• Cambric vs poplin: choosing a shirting base

  How two market names map onto real constructions — and how two fabrics sharing a weight band still behave differently.

• Greige vs RFD vs PFD

  Once the construction is settled, this is the next decision: which processing base your route needs.

• How to source fabric from Pakistan

  Where the construction sits in a complete brief, and what else has to be on it.

• Low-MOQ fabric sourcing from Pakistan

  The confirmed minimums each weight band falls under, and how to work below them.

• Standard greige constructions: a reference table

  The lookup this method unlocks — real register constructions with count, density and status.

• Air-jet vs rapier vs shuttle looms

  The machines behind the notation — what the loom type means for selvedge, defects and routing.

Frequently asked questions

On typical values: this guide explains how to read and use construction notation. Exact outcomes vary by fibre, construction, finishing route and supplier, and should be confirmed on an approved physical sample.