Quilting Block Calculator

Get exact cutting dimensions for HSTs, Flying Geese, hexagons, and more. Enter your finished size and seam allowance.

Half-Square Triangle

Results update as you type.
in
in
blocks
Your cutting numbers
Cut squares at 3-7/8" × 3-7/8"
  • From 2 squares, you get 2 HST blocks
  • Finished size 3" × 3"
  • Unfinished (with seam allowance) 3-1/2" × 3-1/2"
  • Squares to cut, each fabric 1

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Common questions

What seam allowance should I use for quilting?

Standard is 1/4 inch (6mm). This calculator defaults to 1/4" but you can change it.

What is a Half-Square Triangle (HST)?

A square block made of two right triangles sewn on the diagonal. One of the most common quilt blocks.

How do I calculate quilt block cutting size?

Add seam allowance to finished size. For triangles, extra fabric is needed because of the diagonal seam. This calculator handles the math.

What size should I cut for Flying Geese?

Depends on method. Traditional uses a rectangle + 2 squares. No-waste uses 1 large + 4 small squares to make 4 geese at once.

How many quilt blocks do I need?

Use the Quilt Size tab. Enter your target dimensions and block size.