Quilter’s Math Etc.

Half Square Triangles (HST): add 7/8″ to your finished size.
Quarter Triangles: add 1 1/4″ to your finished size

Setting Quilt Blocks on a Diamond

Corner Setting Triangles (Half Square):

Finished size of block (e.g. 12″) ÷ 1.414 + .875 = SIZE

Side Setting Triangles (Quarter Square):

Finished size of block (e.g. 12″) x 1.414 + 1.25 = SIZE

Fraction to Decimal Conversion Chart:

1/8 yd = .13 1/4 yd = .25 1/3 yd = .33
3/8 yd = .38 1/2 yd = .5 5/8 yd = .63
2/3 yd = .67 3/4 yd = .75 7/8 yd = .88

Mattress Sizes:

Crib 23″ x 46″
Twin 39″ x 75″
Double 54″ x 75″
Queen 60″ x 80″
King 76″ x 80″
Quilt Sizes:

Quilt Size Amount of backing needed

Twin 71″ x 101″ 6 yds
Full 86″ x 101″ 7.5 yds
Queen 92″ x 106″ 8.25 yds
King 108″ x 106″ 9.25 yds