Half-Square Triangle Calculator
Calculate the starting square size for half-square triangles (HSTs) based on finished size, seam allowance, and construction method.
Inputs
in
in
Results
Starting Square Size
3.88 in
Unfinished HST Size3.5 in
HSTs per Pair of Squares2
MethodTwo-at-Once
Starting Squares for 20 HSTs10
Trim-to Size3.5 in
How to Use This Calculator
- Enter Finished HST Size, Seam Allowance, and Construction Method.
- Set Two-at-Once (standard), Four-at-Once, and Eight-at-Once.
- Review the Starting Square Size result.
- Use Unfinished HST Size and HSTs per Pair of Squares to inform your decision.
- Use the chart to visualize the results and explore different scenarios by adjusting inputs.
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