Fabric Weight Converter: GSM to Oz
Convert fabric weights, understand how they feel, and find the right bag for your project.
Convert a fabric weight
340 GSM ≈ 10 oz/yd² Heavyweight
Show precise value
10.03 oz/yd²
Heavier fabric for substantial reusable shoppers and totes. Canvas with real structure that holds its shape when full. The classic weight for reusable shoppers and retail totes.
Fabric weight measures the cloth per unit of area, not the weight of the finished bag. GSM is grams per square metre; ounces here are ounces per square yard (oz/yd²), never fluid ounces or ounces per linear yard.
GSM = oz/yd² × 33.905747. Headline figures are rounded; the precise value is always available above, and bag matching always uses the unrounded figure.
How cotton and canvas weights feel
| Description | GSM | oz/yd² | Good for |
|---|---|---|---|
| Lightweight | 0 – <150 | ≈ 0 – 4 | Light, easy-to-fold fabric for simple promotional bags. |
| Midweight | 150 – <250 | ≈ 4 – 7 | A more substantial option for everyday promotional totes. |
| Heavyweight | 250 – <400 | ≈ 7 – 12 | Heavier fabric for substantial reusable shoppers and totes. |
| Premium | 400+ | ≈ 12+ | Extra-heavy fabric for customers seeking a substantial canvas feel. |
These bands are our shopping guide for cotton and canvas bag fabrics, not a textile standard. "Premium" names the heaviest band: finish, construction, lining and handles also decide how premium a bag feels, so we never award a quality badge from fabric weight alone.
Bags at this fabric weight
16 bags match approximately 340 GSM, showing 1 to 12.
Searching 323 to 357 GSM (±5%). This is a matching allowance, not a manufacturing tolerance.
Fabric weight questions
What does GSM mean for bag fabric?
GSM is grams per square metre: how much one square metre of the cloth weighs. It describes the fabric itself, not the finished bag. A higher GSM means a denser, thicker fabric, so a 340 GSM canvas tote feels far more substantial than a 135 GSM promotional tote.
What is oz/yd²?
Ounces per square yard is the imperial version of the same idea and the unit most canvas suppliers quote, so you will see bags described as 4 oz, 8 oz, 10 oz or 12 oz cotton. It is not fluid ounces and not ounces per running (linear) yard. To convert, multiply oz/yd² by 33.905747 to get GSM, or divide GSM by 33.905747 to get oz/yd².
How many GSM is 10 oz canvas?
10 oz/yd² is 339.06 GSM, so it is usually rounded to about 340 GSM. Suppliers list the same cloth either way, which is why our bag finder treats a 10 oz listing and a 340 GSM listing as the same fabric weight while still telling you which figure the product page states.
Which fabric weight should I choose for a tote bag?
Think about how the bag will be used. Lightweight cotton (under 150 GSM, about 4 oz) folds flat and suits giveaways at exhibitions and events. Midweight cotton (150 to under 250 GSM, roughly 5 to 7 oz) is the everyday promotional tote. Heavyweight canvas (250 to under 400 GSM, about 8 to 12 oz) holds its shape and suits reusable shoppers and retail bags. Our Premium band, 400 GSM and above, is for a really substantial canvas feel. Heavier cloth also costs more and prints differently, so tell us the purpose and budget and we will recommend a weight.
Does a heavier fabric always mean a better bag?
No. Weight is one part of quality. Stitching, handle construction, lining, base reinforcement, the fibre (organic, Fairtrade or recycled cotton, jute, polyester) and the finish all matter, and a well-made 8 oz tote can outlast a poorly made 12 oz one. That is why "Premium" here only names our heaviest weight band and is never awarded to a product because of its GSM alone.
Does the finder use exact matches?
When you enter a number we search a small allowance either side of it (initially ±5% of the unrounded GSM) and label bags that are listed at exactly that weight separately from bags with a similar weight. The allowance is a matching convenience, not a manufacturing tolerance. When you choose a description we use the band boundaries exactly. Only bags whose fabric weight our team has verified are shown.