Sometimes a quilter will need to figure out exactly how much yardage is meant in a pattern by doing a little bit of math. and the most common calculation is to convert fabric measurements from one kind of unit into another. Often you are given a measurement in yards, but you need to know how that translates into inches. Or you are given a decimal measurement, such as 1.3 yards, and you need to know how many inches are in that .3!

Below are two handy charts that make that an easy task. I’m also explaining how these calculations are made in case you ever need to wrangle them yourself.

Fractions to Decimals

FRACTION	DECIMAL
1/8	.125
1/4	.25
1/3	.33
3/8	.375
1/2	.5
5/8	.625
2/3	.66
3/4	.75
7/8	.875

How to convert fractions to decimals:

You may remember learning in grade school that a fraction is just a fancy way to write a division problem.  The number on top is divided by the number on the bottom.

And that’s all you do to make the conversion.  So, to convert 1/8 to a decimal, whip out your calculator and divide 1 by 8.  The result will be .125.”

Converting Yards to Inches

YARDAGE FRACTION	AMOUNT IN INCHES
1/8	4.5″
1/4	9″
1/3	12″
3/8	13.5″
1/2	18″
5/8	22.5″
2/3	24″
3/4	27″
7/8	31.5″

How to calculate yards to inches:

First, remember that 1 yard = 36 inches. To make the conversion, you must multiply the yardage fraction by 36. To convert 1/8 yard to inches, here is what you would do:

First convert 36 to a fraction.  Since 36  is a “whole number,” you can convert it to a fraction by putting 36 over 1 (i.e.  36/1 ). You then multiply 36/1 x 1/8.

The trick to multiplying two fractions is to first multiply the two top numbers (36 x 1 = 36) and then multiply the two bottom numbers (1 x 8 = 8). This results in 36/8, which equals 4.5.”

Likewise, if you are multiplying 5/8 x 36/1, you would multiply 5 x 36 together to get the top number (180) and 8 x 1 to get the bottom number (8).  This results in 180/8, which equals 22.5.”