If you've ever wondered why one canvas feels like a sturdy tote bag and another feels like a tent, the answer is the weight — measured in ounces per square yard. Cotton duck canvas comes in a wide range, from a 10 oz that sews on a home machine to a 24 oz built for machinery covers. Pick the wrong weight and your project either flops or fights your sewing machine. This guide explains what the numbers mean and which weight fits your project.
What is cotton duck canvas?
Cotton duck — sometimes called duck cloth or duck canvas — is a plain-weave cotton fabric, woven tighter and heavier than ordinary canvas, with a double fill that gives it its famously sturdy hand. The word "duck" comes from the Dutch doek, meaning cloth. It is 100% cotton, holds its shape, takes dye and print well, and softens with every wash while keeping its structure for years.
What it's best for: tote bags, aprons, workwear and chore coats, upholstery, slipcovers, duffel bags, backpacks, tarps, awnings, and equipment covers. If a project needs to hold its shape and take abuse, duck canvas is usually the right call.
What do the ounce weights mean?
Duck canvas is measured in ounces per square yard (oz/yd²). Higher ounces mean a heavier, thicker, stronger, and stiffer fabric. The same fabric line often comes in several weights, so the weight — not the name — is what you should compare.
There is also an older "number duck" system, graded 1 to 12, where a lower number means a heavier fabric (No. 12 is the lightest, No. 1 the heaviest). Sources differ slightly on the exact ounces per number, so treat the ounce weight on the listing as the authority and the number as a rough guide.
The full range: weights, widths, and what they're for
This is the range we stock — 100% cotton duck, plain weave with a double fill, cut to order from full rolls in Los Angeles. Weights are ounces per square yard, the way duck is measured in the trade.
| Weight | GSM | Widths | Best for |
|---|---|---|---|
| 10 oz | 339 gsm | 60″ | Light apparel, tote bags, aprons, drop cloths, backdrops, bag linings |
| 12 oz | 407 gsm | 60″ | Apparel and chore coats, totes that hold their shape, work aprons, cushion covers |
| 12.5 oz | ~424 gsm | 60″ | Apparel, bags, and upholstery in seven dyed colors |
| 15 oz | 509 gsm | 36″ · 48″ · 60″ | Workwear and apparel, structured bags, upholstery, shop aprons, equipment covers |
| 18 oz | 610 gsm | 58″ · 60″ | Outerwear, work pants and heavy apparel, tote bags, furniture upholstery, floor cloths |
| 20 oz | 678 gsm | 36″ · 60″ | Hard-use covers, industrial bags, hammocks, tool rolls, boat and truck covers |
| 24 oz | 814 gsm | 48″ | The heaviest we stock: tarps, machinery covers, gear that gets abused |
How to pick a weight
10 to 12 oz — the sewing weights. They feed through a home machine without a fight, take a crisp fold, and still hold a bag upright when empty. Light enough for shirts, chore coats, and unlined jackets, and the place to start for totes and aprons.
15 oz — the middle of the line, and the one most people end up on. Enough body for a bag that stands on its own or a chair seat that will not stretch, still soft enough to sew without special tools. It comes in three widths, so there is usually one that cuts with little waste.
18 oz — the workwear weight, what chore coats and work pants are built from. It breaks in rather than wears out. Expect to use a heavier needle and a walking foot.
20 to 24 oz — the industrial end. Stiff out of the roll, close to weatherproof once it swells, and built for things that live outside or take a beating. Too heavy for garments; a domestic machine will struggle past 20 oz.
Widths, and why they matter
We stock 36″, 48″, 58″, and 60″ widths depending on weight. Wider is not automatically better — you pay for every inch, so the right width is the one your pattern nests into with the least waste. A 36″ roll often beats a 60″ on narrow pieces like straps, gussets, and aprons. Measure your longest pattern piece before you choose.
Cotton duck canvas at The Fabric Lot
Our canvas range is built on the same 10–24 oz line: 100% cotton, plain double-fill weave, cut to order by the yard. The dyed range is a 12.5 oz, 60″ canvas in seven colors — Iron, Denim, Orange, Dark Slate Blue, Slate Gray, Dark Navy, and Midnight — at $14.97 per yard. The undyed natural line runs the full 10–24 oz range, from $12.55 per yard for 10 oz natural up to $24.10 for 24 oz natural; the 18 oz workwear weight also comes in ten piece-dyed colors (Black, Cadet Grey, Code Red, Coffee, Dark Green, Marie Gold, Night Fury, Old Navy, Royal Blue, and White) at $18.89 per yard. Every cut ships as one continuous piece, and orders up to 25 yards ship as a single piece.
Shop the full cotton duck canvas range by the yard.
Is duck canvas waterproof?
Not quite. Cotton duck is naturally water-resistant thanks to its tight weave, and it gets closer to weatherproof once the fibers swell with moisture — but it is not waterproof. Waxing or a DWR (durable water repellent) finish makes it genuinely water-repellent; waxing slightly reduces breathability. For tarps and outdoor covers, the 20–24 oz weights plus a wax finish are the usual combination.
Shrinkage and pre-washing
Expect about 3–5% shrinkage on the first wash for this line. Always machine wash cold and tumble dry low to preshrink before cutting — a bag or garment cut from unwashed duck will come out smaller than the pattern. (Some untreated canvas can shrink more; the 3–5% figure is the spec for the line we stock.) Cotton duck softens with every wash and keeps its structure for years.
Dyeing and printing
The natural, undyed duck is unbleached, so it takes fiber-reactive and natural dyes evenly and holds screen and block print clean. Wash it first to clear any mill residue. The piece-dyed colors are already finished and are not meant to be overdyed.
Care
Machine wash cold, tumble dry low to preshrink before cutting. Avoid bleach, air dry if you can, and store dry to prevent mildew.
Sewing tips
Use a heavy-duty needle (size 100/16 or 110/18 for the heavier weights), heavier thread, and go slow. Weights up to 18 oz are manageable on a sturdy home machine with the right needle; past 20 oz you will want a walking foot, and a basic home machine will struggle. Press seams with steam — duck takes a crisp press, which is half the reason it looks so good in finished bags and coats.
FAQ — cotton duck canvas
1. What is cotton duck canvas? A plain-weave 100% cotton fabric, woven tighter and heavier than ordinary canvas with a double fill. "Duck" comes from the Dutch doek (cloth). It's stiff, strong, holds its shape, and softens with washing.
2. What do the ounce weights mean — and what are the number duck classifications? Ounces per square yard: higher oz means heavier, thicker, stronger, stiffer. Our range runs 10 oz (339 gsm) to 24 oz (814 gsm). The older number-duck system grades 1 to 12, with a lower number meaning a heavier fabric (No. 12 lightest, No. 1 heaviest). Sources differ slightly on exact ounces per number, so use the ounce weight on the listing as the authority.
3. What weight canvas do I need for tote bags? 10–12 oz for light, everyday totes that sew easily on a home machine; 15 oz if you want a bag that stands on its own; 18 oz for heavy, structured totes. Our 12.5 oz dyed line ($14.97/yd) is a good middle ground for bags.
4. What weight canvas do I need for upholstery? 15 oz for chair seats and cushion covers that need body without being impossible to sew; 18 oz for furniture upholstery and floor cloths that take real wear. Both come in widths up to 60″.
5. What weight canvas do I need for tents and tarps? 20–24 oz. The 24 oz (814 gsm, 48″ wide) is the heaviest we stock and is built for tarps and machinery covers. Pair it with a wax finish for real water resistance.
6. Is cotton duck canvas waterproof? No — naturally water-resistant, not waterproof. The tight weave sheds light rain, and the fibers swell when wet, but for true water resistance you need waxing or a DWR finish.
7. Does cotton duck canvas shrink? Yes — expect about 3–5% on the first wash for the line we stock. Pre-wash cold and tumble dry low before cutting, and you'll avoid surprises.
8. How do you wash and care for duck canvas? Machine wash cold, tumble dry low, avoid bleach, air dry when you can, and store dry to prevent mildew. It softens with every wash.
9. What's the difference between duck canvas and regular canvas? Duck is a specific, tighter, heavier plain weave made exclusively from cotton, with a double fill; regular canvas can be looser, lighter, and made from other fibers. Duck holds its shape better and is the standard for bags, workwear, and covers.
10. Can you sew duck canvas on a home sewing machine? Yes, up to about 18 oz, with a heavy-duty needle and heavier thread. The 10–12 oz weights feed through a home machine without a fight. Past 20 oz you will want a walking foot, and a basic home machine will struggle — that's industrial-weight territory.
Shop canvas fabric by the yard · tote & utility fabric · fabric by the yard in Los Angeles. Related: fabric specs checklist.