Half-Square Triangle Trim Plan

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.