Army duck / numbered duck: the weight chart, and what each number is for
Numbered duck, or army duck, is cotton duck graded on a US scale that runs from about No. 12 (lightest) to No. 1 (heaviest). A lower number is a heavier cloth — the scale is a legacy of military and sailmaking specification and still turns up in luggage, footwear and cover specs.
The chart
| Number | oz/yd² | g/m² (approx) | Typical use |
|---|---|---|---|
| No. 12 | ~7 oz | 230 | Light bags, garment interlining, book cloth |
| No. 10 | ~8 oz | 270 | Tote and utility bags, light footwear |
| No. 8 | ~10 oz | 340 | Tool bags, footwear uppers, aprons |
| No. 6 | ~12 oz | 410 | Luggage, sacks, equipment covers |
| No. 5 | ~13.5 oz | 460 | Heavy bags, structured cases |
| No. 4 | ~15 oz | 510 | Heavy covers, upholstery base, floor cloth |
| No. 2 | ~17 oz | 580 | Industrial covers, shelters |
| No. 1 | ~19 oz | 640 | Structural, marine, heaviest covers |
Figures are indicative — the exact weight depends on the construction behind the number.
What "numbered" actually means
Numbered ducks are woven 2-ply: two-ply yarn in both warp and weft. That is what gives them the firm, flat, even face and the structure that single-fill duck of the same weight does not have. When a spec says "No. 8 army duck", it is asking for that 2-ply construction at roughly 10 oz, not just any 10 oz duck.
Spec'ing it
- If your reference is a number, we match the weight and the 2-ply construction.
- If your reference is an oz or g/m² figure, we map it to the nearest number and confirm the construction.
- If you have a swatch, we pull it apart, identify the yarn count and ends/picks, and quote a match.
We weave the numbered range to 140 inches wide, so wide cover and upholstery panels come off without a seam.