9 Patch Quilt Calculator
This calculator helps quilters find out the cut sizes for squares, half-square triangles, and stem units when creating a 9-patch quilt block.
To find out, enter the desired finished block size and click “Calculate Sizes.”
The calculator will then display the required cut sizes for each component, making it easier to plan and create your 9-patch quilt block.

What is 9 patch quilt pattern?
A 9-patch quilt pattern consists of quilt blocks made up of 9 squares arranged in a 3×3 grid. The nine-patch block is created by sewing together 9 squares with a 1/4″ seam allowance and may be produced with any size squares.
Because of its simplicity, it is considered a beginner-friendly block, and it can be simply adjusted and combined with other blocks to produce a variety of quilt designs.
What is the formula for 9 patch quilt?
- For Squares: Finished size + 0.5
- For Half-Square Triangles (HSTs): Finished size + 1
Stem unit
- Background fabric: Cut size = Finished size + 0.5
- Stem width: New stem width = (Known stem width / Known finished patch size) × Desired finished patch size

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