Do you find yourself dreading quilt math? Well dread no more with this Half Square Triangle calculator! Simply plug in the size you want your HSTs to finish at, and the calculator will do the math for you! Once you type in your finished HST size, use the measurements on the right. They’ll indicate which size squares you need to cut to create the HSTs you want. You’ll get measurements for 2-at-a-time, 4-at-a-time, and 8-at-a-time methods. The calculator gives you measurements in inches.
For 4-at-a-time Half Square Triangles, round the number up to the nearest 1/4″. For example, if the calculator tells you to cut 9.375″ squares, round up to 9.5″ and cut two squares that size to make your HSTs.
FYI! Finished size means the size once it is all sewn into your project. Unfinished size is the size you trim to when creating your HSTs. You’ll use the finished size in your measurements below, but remember to trim HSTs 0.5″ bigger!
Half Square Triangle Calculator
Size Squares to Cut:
Having trouble with the Half Square Triangle Calculator? Try it on desktop!
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Additional Half Square Triangle Resources:
If you’re new to making Half Square Triangles, I have a handy printable guide with step-by-step diagrams for all three methods! If you’re looking for help trimming, I’ve got two separate videos to help with that too!
Includes step-by-step tutorial for 2-at-a-time, 4-at-a-time, and 8-at-a-time half square triangles & printable cheat sheet!
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