— Fabric weight tool
GSM to oz converter.
Type into either field — GSM or oz/yd² — and the other updates instantly. Free fabric weight calculator, built from the same GSM math used to spec the 1ABEL catalog.
— What GSM means
GSM, explained
GSM stands for grams per square meter. It's the standard way fabric weight is measured — cut a one-meter square of the fabric, weigh it in grams, and that number is the GSM. Heavier GSM means denser, more durable fabric that holds its shape and drapes with more structure. Lower GSM means lighter, more breathable, less durable fabric.
In the US, fabric weight is more often quoted in ounces per square yard (oz/yd²) — the imperial equivalent. Both describe the same thing: how much a fixed area of fabric weighs. GSM is the number you'll see on most fabric mills' spec sheets and on garment tags outside the US; oz/yd² is what US brands like Hanes and Pro Club use to market tee weight.
— The formula
GSM to oz conversion formula
The conversion is fixed by the ratio between grams-per-square-meter and ounces-per-square-yard:
1 oz/yd² = 33.906 g/m²
GSM = oz × 33.906 · oz = GSM ÷ 33.906
— Fabric weight chart
Fabric weight classes, by GSM
Every fabric weight falls into a rough class. Here's where the common benchmarks — including the Hanes Beefy-T, Pro Club, and the 1ABEL catalog — land.
| Class | GSM | oz/yd² | Examples |
|---|---|---|---|
| Lightweight tee | < 180 GSM | < 5.3 oz | Budget basics, summer-weight tees, most fast-fashion cotton tees. |
| Standard tee | 180 – 200 GSM | 5.3 – 5.9 oz | Most mid-tier retail tees — enough body to survive a wash cycle. |
| Heavyweight tee | 200 – 260 GSM | 5.9 – 7.7 oz | Hanes Beefy-T 6.1oz ≈ 207 GSM · Pro Club 6.5oz ≈ 220 GSM · 1ABEL tee, 220 GSM. |
| Rugby / ultra-heavy | 260 – 320 GSM | 7.7 – 9.4 oz | Rugby shirts, heavy canvas tees — starts to feel like sweatshirt fabric. |
| Fleece / hoodie | 300 – 550 GSM | 8.9 – 16.2 oz | Standard hoodies 340–400 GSM · 1ABEL hoodie, 550 GSM heavyweight fleece. |
The 1ABEL catalog runs 220 GSM ring-spun cotton for the heavyweight tee and 550 GSM cotton fleece for the hoodie — both landing at the top end of their weight class on purpose.
— FAQ
Common GSM questions
What is 6.1 oz in GSM?
6.1 oz/yd² converts to approximately 207 GSM (206.8 g/m² using the 33.906 conversion factor). That's the fabric weight of the Hanes Beefy-T, one of the original heavyweight-tee benchmarks.
What is 6.5 oz in GSM?
6.5 oz/yd² converts to approximately 220 GSM (220.4 g/m²) — the weight of Pro Club's popular heavyweight tee, and the same weight as the 1ABEL tee.
What is a good GSM for a t-shirt?
200–220 GSM is the sweet spot for most everyday tees: heavy enough to hold structure and drape well, light enough to wear year-round. Below 180 GSM starts to feel thin or see-through; above 260 GSM edges into rugby or sweatshirt territory.
What is 550 GSM?
550 GSM is a heavyweight fleece — roughly 16.2 oz/yd². It's used for premium hoodies built to hold shape and insulate, like the 1ABEL hoodie. Most mass-market hoodies sit at 300–400 GSM.
What does GSM mean in clothing?
GSM stands for grams per square meter — a direct measurement of how much a square meter of fabric weighs. It's the metric-system standard for fabric weight; oz/yd² (ounces per square yard) is the imperial equivalent used mostly in the US.