Wool Fabric Yardage: Nap, Width, and Matching
Most wool has a direction, and direction is what costs you fabric. Once every piece has to face the same way, half the tricks for packing a layout tightly stop working.
Your Pattern Envelope Already Solved This
Turn a commercial pattern over and you will often find two yardage figures for the same size and view. One is labelled without nap and one with nap. The second is nearly always larger, and for wool it is the one you want.
The reason is simple once you see it. A layout without nap is free to spin pieces round so a wide end tucks beside a narrow one, which packs them tightly. A with nap layout has every piece pointing the same way, so those gaps stay empty. The pattern company already measured both. You do not need to add a percentage on top of the with nap figure, and doing so is the most common way people over buy wool.
If you are working without a commercial pattern, the sewing calculator will give you a starting estimate by garment type.
How to Tell Whether Your Wool Has a Nap
Lay a length flat under the light you can see best in, ideally daylight. Stroke your hand down it, then up it. On a napped cloth the surface fibres lie one way and stand up the other, and the colour shifts between the two: darker one way, lighter the other.
Then do the test that actually decides it. Cut two pieces, turn one upside down, and lay them edge to edge. If you can see the join across the room, you have a nap and you are committed to a one way layout. Melton, flannel, camel hair, and anything brushed or fleecy will usually fail this test. Flat worsted suiting often passes.
Do it while the fabric is still on the bolt if you can. Finding out after cutting is how a coat ends up with one sleeve visibly darker than the other.
Why 60 Inch Yardage Will Not Scale Down to 54
Say the envelope gives 2.75 yards on 60 inch cloth and 3.5 yards on 54 inch. It is tempting to think the ratio explains it: 2.75 × 60 ÷ 54 comes out at 3.06 yards. The real answer is 3.5, and the missing half yard is not rounding.
Here is what happened. A coat front measuring 28 inches at its widest fits two to a row on 60 inch cloth, because 28 and 28 make 56. On 54 inch cloth it does not, so those two fronts now need two rows instead of one. If the front is 40 inches long, that single change adds 40 inches of length, which is most of the gap.
| Wool type | Usual width | Napped? |
|---|---|---|
| Worsted suiting | 58–60" | Often not |
| Flannel | 54–60" | Usually yes |
| Coating and melton | 54–60" | Almost always |
| Crepe | 54–58" | Usually not |
| Upholstery wool | 54" | Varies, check |
This is why a width ratio is unreliable in either direction. Yardage moves in steps, not on a slope, and the steps happen when a piece stops fitting beside its neighbour. If you have to work it out yourself, trace your widest pieces at scale and shuffle them on paper. The fabric width guide goes further into where those steps fall.
Wool Moves When It Meets Heat and Steam
Do not treat wool like cotton here. Hot water plus agitation is how wool felts, and a felted length is smaller, denser, and not coming back. That rules out simply putting it through the machine to preshrink it.
The usual approach is steam rather than water. Tailors have long relaxed cloth by steaming it before cutting, and many dry cleaners will do it for you on request. At home a common method is hovering a steam iron just above the surface without pressing down, working across the whole length, then leaving it flat to dry and cool completely before anything gets cut.
Whatever route you pick, try it on a marked offcut first and measure before and after. How much a particular wool moves depends on its weave and finish, so a figure from a chart is a poor substitute for a test on your own cloth.
The Woolmark care library is a reasonable general reference. The label on your specific cloth still wins, and that resource does not validate the yardage maths here.
Checks and Stripes Arrive With a Separate Bill
A nap allowance and a matching allowance are two different things, and a large check wants both. Nap fixes the direction every piece faces. Matching decides where along the cloth each piece is allowed to start.
A rough working figure is one extra repeat of length for every seam that has to match. On a 6 inch check with four seams you care about, that is 24 inches, or two thirds of a yard, before you have cut anything. Small even checks are cheap. Large, uneven, or boldly coloured ones are not, and it is worth deciding how strictly you want to match before you order rather than after.