Open Measurements in the studio. The form on this page is that calculator.
Why fabric math is in eighths
Patterns mix fractions, decimals, and centimeters. Shops in the US sell by the eighth of a yard. An eighth is 4 1/2 inches. Ask for 0.4 yards and you will be sold half a yard or three eighths, whichever the cutter rounds to, and you should know which you actually needed. The card shows the decimal and the next eighth up. Buying the eighth up is the safe direction.
The other job on this page is a change of width. Two yards of 42 inch fabric is the same area of cloth as less than a yard of 108 inch wide backing, before you think about which way the seam has to run. Width conversion matches the area. It does not tell you the seams. The backing calculator does.
How the conversion is calculated
- A yard = 36 inches = 91.4 centimeters
- An eighth of a yard = 4 1/2 inches
- Shop cut = the decimal yards, rounded up to the next eighth
- A new width = (yards × width you have) ÷ width you are buying, then rounded up to the next eighth
One and a half yards is 54 inches, which is 137.2 centimeters. Two yards of 42 inch cloth is 7/8 yard of 108 inch cloth, and 1 7/8 yards of 45 inch cloth. The wider bolt is the one that usually removes a backing seam. The narrower one does not.
Yardage in inches and centimeters
Centimeters are rounded to one decimal, the way the card prints them. The shop still cuts the eighth of a yard.
| Ask for | Inches | Centimeters |
|---|---|---|
| 1/8 yard | 4 1/2 | 11.4 |
| 1/4 yard | 9 | 22.9 |
| 3/8 yard | 13 1/2 | 34.3 |
| 1/2 yard | 18 | 45.7 |
| 5/8 yard | 22 1/2 | 57.2 |
| 3/4 yard | 27 | 68.6 |
| 7/8 yard | 31 1/2 | 80.0 |
| 1 yard | 36 | 91.4 |
| 1 1/2 yards | 54 | 137.2 |
How to use this calculator
- Choose convert when you have one length and want it in inches, yards, centimeters, and meters.
- Type the amount and the unit it is in. 1.5 yards and 54 inches are the same length.
- Choose a different width when you already know the yardage at one bolt width and you are buying another. Enter both widths.
- Buy the eighth the card rounds up to. A backing still needs the <a href="/quilt-backing-calculator">backing calculator</a> to check the seams.
Tips for shop math
- Write the eighth on the list, not the decimal from a pattern drafted in another country. The cutter works in eighths.
- 108 inch backing is a different layout, not just a smaller number of yards. Confirm the quilt fits the width before you trust the area.
- Metric patterns in centimeters convert cleanly here. A meter is 39.37 inches, a little more than a yard.
When the piece is part of a whole quilt. The studio's yardage is already in shop eighths. This page is for a number you met somewhere else. The fabric calculator counts every piece in a design, then adds binding, backing, and batting. These pages answer one question at a time.