How Much Fabric Do You Need?
For 12 napkins cut 18 × 18 in from 42 in quilting cotton, buy 3 yd. Enter your own pieces in the calculator above. It works out how they fit across the fabric, how much length that takes and how much to buy, then draws where to cut each piece.
How to Use the Fabric Calculator
- Choose your fabric width, or choose Custom and enter what you measured.
- Enter each piece: its width (across the fabric), its length (along the fabric) and how many you need. Use Add piece for more sizes.
- Open More options if you need seam allowance, a directional print, a pattern repeat, extra for shrinkage, a different rounding step or a price.
The result shows the amount to buy, a cutting layout drawn to scale, a cut list and any fabric left over. You can copy it, print it or share a link.
How the Calculation Works
Fabric comes off the bolt at a fixed width, so the question is how much length you need. Here’s the napkin example step by step:
- Pieces across: 2 napkins fit side by side (36 in of the 42 in).
- Rows: 12 napkins, 2 per row, make 6 rows.
- Length: 6 rows of 18 in is 108 in.
- Amount to buy: 108 in is exactly 3 yd. When the length falls between steps, the calculator rounds up, never down.
With pieces of different sizes, the calculator tries several layouts, turning pieces sideways where that helps (unless the print is directional), and keeps the one that needs the least fabric.
Why shortcuts give the wrong answer
Two quick methods are often off, one way or the other:
- Area only. The napkins cover 3,888 sq in. Divide that by the fabric width and you get about 93 in, or 2 5/8 yd. That’s about 15 in short, because pieces can’t use the 6 in strip left down the side.
- One piece per row. Stacking the napkins one below another takes 216 in, or 6 yd: twice what you need.
Cut Size vs Finished Size
Check whether your sizes include seam allowance, the margin you sew along. If your pattern gives cut sizes, enter them as they are. If you have finished sizes, turn on Add seam allowance to each piece: with 1/4 in on each side, the napkins become 18 1/2 × 18 1/2 in and you need 3 1/8 yd.
The calculator adds nothing extra unless you ask; some calculators quietly add 5–10%. Cotton can shrink 3–5% the first time it’s washed, so if you prewash, add about 5% under Extra for shrinkage and mistakes. For the napkins, that’s 3 1/4 yd.
Common Fabric Widths
Shops label fabric by its full width, from one selvage (the firm woven edge) to the other. The quilting cotton and wide backing buttons in the calculator use the usable width, once the selvages are trimmed; the apparel and home decor buttons use the labeled width. If your pieces only just fit across, measure the width you can actually use and enter it under Custom. These are the usual widths and the matching buttons:
| Fabric | Usually sold as | Button in the calculator |
|---|---|---|
| Quilting cotton | 44/45 in | 42 in |
| Apparel fabric | 45 in or 58/60 in | 45 in or 58 in |
| Home decor fabric | 54 in | 54 in |
| Wide quilt backing | 108 in | 104 in |
For 58/60 in fabric, the calculator uses 58 in, the smaller of the two.
Buying Fabric by the Yard
A yard is 36 in (91.44 cm). Shops in the US cut fabric in steps, often 1/8 yd (4 1/2 in), so the calculator rounds up to the next step and shows it as a fraction you can ask for at the counter. Some shops cut only quarter yards, half yards or whole yards; choose that step under More options. A third of a yard is 12 in, and the yard chart below shows every common fraction in inches and centimeters.
Yards and meters aren’t the same: a meter is 39.37 in, about 1.09 yd, so a length in meters is a little more fabric than the same number of yards. The calculator switches to centimeters and meters with one tap.
To work out the cost, multiply the price per yard by the amount you buy, not the exact length: 3 yd at $12.99 a yard is $38.97.
Tips Before You Cut
- Directional prints: if the print has an up and a down, turn on Directional print so no piece is turned sideways.
- Pattern repeat: to match a print across pieces, enter the repeat (how far down the fabric before the print repeats).
- Prewashing: prewash cotton before you measure and cut, so the pieces don’t shrink after sewing.
- Measure twice: check your piece sizes and the fabric’s usable width before you cut.
Quilts and Curtains
Making a quilt? The quilt backing calculator compares seam directions and wide backing, and adds batting and binding. Sewing curtains? The curtain fabric calculator handles fullness, half widths, pattern repeats and lining.