GSM Fabric Weight Chart: Every Weight from 150 gsm to 700 gsm, Converted

This is a reference chart, not an essay. Below is every fabric weight you are likely to meet on a knit apparel quote, converted to ounces, matched to what it is actually used for and what it feels like in the hand. Then the arithmetic: how the measurement is taken, how to convert it, and what a change in weight costs you per unit once duty is on top. It sits inside sourcing apparel direct from factories, alongside how to write a complete fabric specification.

One vocabulary note before the chart. Buyers say "cloth gsm", "fabric weight", "grammage" and "GSM" for the same measurement, and US vendors say "ounces" for a converted version of it. They are all grams per square metre of finished cloth. Nothing in this article changes depending on which word your supplier uses.

GSM fabric weight chart: 150 gsm to 700 gsm with oz/yd² equivalents

Knit fabric weights, ounce conversions, end use and hand-feel. Ounce figures are gsm ÷ 33.9, rounded to one decimal. Weights from 140 to 340 gsm are the published knit benchmarks; the 340–480 gsm bands follow supplier fleece guidance; anything above that is outside normal apparel knit practice and is flagged as such.

Weights below 340 gsm come from published knit benchmarks; the 340–480 gsm bands follow hoodie fleece guidance from suppliers rather than a standards body, so treat them as commercial convention rather than a specification. The rib weights used for necks and cuffs vary widely by mill and should be specified separately from the shell.

How fabric weight is measured, and why greige and finished GSM differ

GSM is measured on finished, relaxed, conditioned fabric. Each of those three words is doing work:

• Finished — after dyeing, compacting and softening. Greige (undyed, unfinished) fabric and finished fabric of the same construction differ by 5–15%. A mill quoting an unqualified "180 gsm" may be quoting greige.
• Relaxed — knit fabric under roll tension reads light. It must be allowed to recover before it is cut and weighed.
• Conditioned — cotton is hygroscopic, so it gains and loses weight with humidity. The standard conditioning atmosphere is 20°C and 65% relative humidity for at least 24 hours (ASTM D1776 / ISO 139).

The test itself is standardised as mass per unit area under ASTM D3776/D3776M or ISO 3801. Write "180 gsm finished, ±5%, tested per ASTM D3776 after conditioning per ASTM D1776" into the spec and the ambiguity is gone.

Calculating gsm from a swatch: the 100 cm² cutter method

Calculating gsm on the floor takes a round GSM cutter and a lab balance. The cutter punches a 100 cm² circle, which is exactly one hundredth of a square metre, so:

GSM = swatch weight in grams × 100

A 100 cm² swatch weighing 1.80 g is 180 gsm. Cut five swatches from different positions across the width and along the roll and average them, because knit fabric is heavier at the selvedge than in the middle on a badly set machine. If you have no cutter, weigh any measured rectangle and divide: a 20 cm × 25 cm piece is 0.05 m², so a 9.0 g piece is 9.0 ÷ 0.05 = 180 gsm.

How to convert gsm to oz, and how to convert 230 gsm to lbs for a roll

US vendors quote oz/yd²; Asian mills quote gsm. 1 oz/yd² ≈ 33.9 g/m².

• To convert gsm to oz: divide by 33.9. 180 ÷ 33.9 = 5.3 oz. 400 ÷ 33.9 = 11.8 oz.
• To convert oz to gsm: multiply by 33.9. A "6.0 oz" tee is 203 gsm; a "4.3 oz" tee is 146 gsm.

Pounds are a different question, because pounds are a quantity unit, not a weight-per-area unit, and mills invoice knit fabric by the kilogram. Work it in three steps. Taking 230 gsm to lbs:

So a "230 gsm" fabric is 0.42 lb per square yard, and a standard 100-metre roll of it weighs about 91 lbs. That last number is the one that matters for freight and for checking a mill's delivery note against the yardage you were invoiced for.

Worked example: what moving from 180 gsm to 240 gsm costs per unit

Fabric is the largest single line on a knit cost sheet, and GSM scales it almost linearly. A 180 gsm single jersey crew tee in a size medium consumes 0.27 kg of finished fabric per piece, including roughly 10% cutting wastage, at a finished dyed jersey price of about $8.15/kg. That is $2.20 of fabric in a $4.30 FOB tee — 51% of FOB.

Fabric weight and fabric cost per tee across five GSM specs, finished dyed jersey at $8.15/kg.

Now take the decision a lot of brands make in year two — moving the core tee from a premium 180 gsm to a boxy 240 gsm streetwear weight:

• Fabric cost rises $0.73 per unit at the mill, about 17% of a $4.30 FOB.
• Duty applies on the higher value. At the August 2026 all-in rate of 26.5% for a cotton knit tee from India or Bangladesh (16.5% MFN plus the 10% Section 301 forced-labor layer), that $0.73 becomes $0.92 landed before freight.
• Across a 10,000-piece order that is about $9,200 of extra landed cost, bought with one number on a spec sheet.

These duty rates are illustrative of the method. Verify against the current HTSUS before relying on a figure, and see US import duty on clothing in 2026 for the current stack. The heavier fabric also consumes more dye chemistry and more container weight, and it pushes you toward higher minimums — the dye-vessel and roll minimums are covered in fabric and dye-lot minimums.

Why GSM alone does not tell you how a fabric will perform

GSM is one number out of four, and on its own it is close to useless as a quality signal.

• Yarn count decides fineness. A 180 gsm fabric knitted from 30s Ne is denser and smoother than a 180 gsm knitted from 20s, because finer yarn needs more loops per unit area to reach the same weight.
• Spinning and preparation decide hand and pilling. Open-end yarn at 240 gsm can feel worse than combed ring-spun at 180 gsm. This is the axis buyers most often confuse with weight — see combed ring-spun cotton and yarn count.
• Structure decides drape and stability. Single jersey curls at the cut edge and is prone to spirality; interlock at the same weight does not curl at all; rib has roughly double the width extensibility of single jersey, which is why it is used for necks and cuffs.
• Finish decides shrinkage. Fabric that meets your GSM and was never compacted will fail your shrinkage test. Cotton knits are mechanically pre-shrunk; write "compacted" into the spec.

Two fabrics at identical GSM, from two mills, are routinely different products. Specify weight, count, spinning, structure and finish together, or the mill picks the cheapest option on every field you left blank. Definitions for GSM, greige, Ne and loopback fleece are collected in the Yarnstick glossary of sourcing terms.

Heavyweight hoodie weights, and what a 700 gsm zip up hoodie actually means

The published fleece benchmark is 280–340 gsm, with 320 gsm the standard hoodie weight. Supplier guidance extends that upward into commercial bands: 340–380 gsm for core streetwear, 400–420 gsm for premium heavyweight collections, and 450–480 gsm for ultra-heavy luxury basics.

One band down, the 600 gsm meaning on a hoodie listing raises the same question. Read as fabric, 600 g/m² is 17.7 oz/yd², about double the 320 gsm standard, so ask whether the figure is fabric weight, finished garment weight or a bonded two-layer construction before comparing it with anything.

Nothing credible sits at 700. When a listing advertises a 700 gsm zip up hoodie, one of three things is usually true: the number is the total finished garment weight in grams rather than the fabric's grams per square metre, the fabric is a bonded or double-face construction where two layers have been counted together, or the figure is simply marketing. A 700 gsm fabric would be 20.6 oz/yd², roughly double the heaviest fleece in commercial production, and would not behave like a garment. Ask which basis the number is on, then ask for a swatch and a lab gsm report — the same question applies whether you are buying blanks or specifying a mill run. Weight-by-weight product ranges are covered in blank hoodies and sweatshirts by weight, and how to buy the fabric itself in how brands buy fabric from mills.

Frequently asked questions