counting yardage in quilts

How to compute yardage used without actually counting it (which I have really done in the past!)

Find the area of the quilt top as w" x l" = Area. 

If you use "small pieces" like 2" patches, multiply Area x 1.5. If you use "bigger pieces" like 3" patches or more, multiply Area x 1.25. 

Example: quilt top is 50" x 60" and is made of "small" pieces. 50 x 60 = 3000. 3000 x 1.5 = 4500. 

Now add the quilt back, which should be the same as the top Area. 

4500 (top) + 3000 (back) = 7500. 

Add your binding. Find your perimeter as (w + l) x 2. (50 + 60)x2 = 110x2 = 220. Multiply perimeter by width of binding. If you use 2.5" binding, 220 x 2.5 = 550 

top + back + binding = square inches 

4500 + 3000 + 550 = 8050 

Now divide square inches by 40 (WOF), then divide again by 36" for number of yards. 

8050/40 = 201.25 

201.25/36 = 5.59 yards. This seems about right for a lap quilt, including the binding. 

So this is good for keeping track of the yardage used. Now to design an excel for expenditures.....