Half square triangles
Half Square Triangle Size Chart: Cut Sizes by Method
Quick answer
For two-at-a-time half square triangles, cut squares 7/8 inch larger than the finished size, or 1 inch larger to trim. Four at a time uses squares about 1.41 times the finished size plus 1 1/4 inches, and eight at a time uses squares twice the finished size plus 1 3/4 inches. A 3 inch HST uses 3 7/8 inch squares.
| Finished | Unfinished | 2 at a time | 2 at a time, trim | 4 at a time | 8 at a time |
|---|---|---|---|---|---|
| 1 1/2 in | 2 | 2 3/8 | 2 1/2 | 3 3/8 | 4 3/4 |
| 2 in | 2 1/2 | 2 7/8 | 3 | 4 1/8 | 5 3/4 |
| 2 1/2 in | 3 | 3 3/8 | 3 1/2 | 4 7/8 | 6 3/4 |
| 3 in | 3 1/2 | 3 7/8 | 4 | 5 1/2 | 7 3/4 |
| 3 1/2 in | 4 | 4 3/8 | 4 1/2 | 6 1/4 | 8 3/4 |
| 4 in | 4 1/2 | 4 7/8 | 5 | 7 | 9 3/4 |
| 4 1/2 in | 5 | 5 3/8 | 5 1/2 | 7 5/8 | 10 3/4 |
| 5 in | 5 1/2 | 5 7/8 | 6 | 8 3/8 | 11 3/4 |
| 6 in | 6 1/2 | 6 7/8 | 7 | 9 3/4 | 13 3/4 |
| 8 in | 8 1/2 | 8 7/8 | 9 | 12 5/8 | 17 3/4 |
For any other size, use the half square triangle calculator.
Researched from manufacturer specifications, owner manuals and verified owner reviews, not hands-on testing, and not professional advice. As an Amazon Associate, Cozy Stitchery earns from qualifying purchases.