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THE FEUTEX TOOLKIT

Square-in-Square Patchwork Geometry

Determine the rotated center square size and its diagonal from the desired finished outer block.

Crafts workspace● Runs in your browser
01 Your input
02 Your result
View or copy raw result data
FormulaFinished center square side = outer/Math.sqrt(2); Center square cut side = outer/Math.sqrt(2)+2*seam+trim

Made for real tasks

  • Determine the rotated center square size and its diagonal from the desired finished outer block.
  • Compare an alternative set of measurements without uploading personal data.
Explore step-by-step workflows →

Worked example

Inputs

Finished outer block side
20 cm
Center seam allowance
0.7 cm
Extra center trim allowance
0.2 cm

Expected results

Finished center square side
14.14213562 cm
Center square cut side
15.74213562 cm

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 finished outer block side, center seam allowance, and extra center trim allowance in the displayed units.
  2. Calculate and use each labeled result for square-in-square patchwork geometry. Compare the result with a measured sample before committing materials.

Try this example

{
  "outer": 20,
  "seam": 0.7,
  "trim": 0.2
}

Accuracy and scope

Ideal center geometry for a rotated square with corners at side midpoints. Side triangle cutting and construction-specific tolerances require a sample.

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.