If you’re sourcing cotton canvas, you’ve probably seen all three terms — duck, canvas, and single fill — used like they mean the same thing. They don’t. And picking the wrong one costs time and money.
What is Canvas, Technically?
Canvas is a broad term — not one specific fabric. It refers to any heavy, plain-woven cloth made for industrial use rather than clothing. That includes Number Ducks, Single Fill Ducks, Army Ducks, drills, twills, and more. A quick note on terminology: In the industry, “duck,” “canvas,” and “single fill” are often thrown around interchangeably — and it causes confusion. So yes, all ducks are canvas. But not all canvas is duck.
What is Duck Canvas?
Duck canvas (Number Ducks) uses plied yarns in both the warp (lengthwise) and fill (crosswise) directions. That means each thread is actually multiple yarns twisted together. Result: heavier, tighter, coarser and much stronger. Number Ducks range from #12 (~11.4 oz) up to 2/0 Naught Duck (~32 oz). These are the fabrics you choose when failure isn’t an option.
What is Single Fill Canvas?
Single Fill ducks use plied yarns in the warp but single yarns in the fill. That single fill yarn makes the fabric lighter, more flexible, and more economical. Single Fill weights typically range from 7 oz to 12 oz. They’re perfect for cost-sensitive projects that still need the cotton canvas look and feel.
Side-by-Side Comparison
| Feature | Duck Canvas (Number Ducks) | Single Fill Canvas |
|---|---|---|
| Yarn Construction | Plied warp × plied fill | Single warp × single fill |
| Weight Range | 11.4 oz – 32 oz | 7 oz – 12 oz |
| Strength | High tensile & tear resistance | Moderate — good for light to medium use |
| Texture | Tighter weave, heavier hand | Softer, more pliable |
| Best For | Tool bags, tarps, industrial covers, pannier bags | Promotional totes, dust covers, linings, giveaways |
| Cost | Higher — more material, more labor | Lower — economical for volume orders |
Which One Should You Choose?
-
Choose Duck Canvas if: Your product takes abuse — sharp tools, heavy loads, outdoor exposure, or rough daily handling. Tool bags, military covers, conveyor belts, saddle panniers. Go with #8, #6, #4 or heavier.
-
Choose Single Fill if: You need the cotton canvas look at a lower price point — promotional tote bags, dust covers, light packaging, or temporary uses. 7 oz or 10 oz Single Fill does the job without overbuilding.
-
Not sure? Try #10 Duck or 10.10 oz Army Duck. Both sit in the middle ground — affordable enough for volume, tough enough to build a reputation on.
Both fabrics are in stock. View our full [Fabric Specification Chart] for ASTM test data, widths, and grade comparisons. Or call +1-843-647-6363 — we’ll help you spec the right fabric for your project.
Ready to order? Call us at +1-843-647-6363 or [request a quote] — we’ll help you pick the right weight for your project.