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THE FEUTEX TOOLKIT

Half-Square Triangle Trim Plan

Plan oversized two-at-a-time half-square triangle units and trimming allowance.

Sewing workspace● Runs in your browser
01 Your input
02 Your result
View or copy raw result data
FormulaTrim size = finished+2*seam; Cut square = finished+2*seam+Math.SQRT2*seam+oversize; Pairs = Math.ceil(units/2)

Worked example

Inputs

Finished
10 cm
Seam
0.6 cm
Oversize
0.5 cm
Units
40 units

Expected results

Trim size
11.2 cm
Cut square
12.54852814 cm
Pairs
20 pairs

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Enter the measured quantities and your own planning assumptions.
  2. Review all calculated outputs and the stated limitations.

Try this example

{
  "finished": 10,
  "seam": 0.6,
  "oversize": 0.5,
  "units": 40
}

Accuracy and scope

Geometric starting allowance for the two-at-a-time method. Make and measure a test pair; fabric stretch and sewing accuracy affect final size.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.