What is sashing in quilting?

Sashing is the fabric strips sewn between quilt blocks to separate and frame them. It creates a grid effect and can make blocks appear to float. Common sashing widths are 3-7cm finished.

What are cornerstones?

Cornerstones (or setting squares) are small squares placed where sashing strips meet. They add a design element and can use a contrasting fabric. They simplify construction as you sew sashing to blocks in rows.

How wide should sashing be?

Sashing width depends on block size and design. A common rule is 1/6 to 1/4 of the block size. For 30cm blocks, 5-7.5cm sashing works well. Narrow sashing (2-3cm) lets blocks blend; wide sashing frames each block.

Should sashing match the background or contrast?

This is a design choice. Matching background fabric creates unity. Contrasting fabric frames each block distinctly. Try both options with your blocks on a design wall before cutting all sashing.

SewCalcs

Sashing Calculator — Sashing Strips & Fabric

Calculate sashing strip quantities and fabric for quilt layouts.

Blocks Across

Block size for quilting

Blocks Down

Block size for quilting

Finished Block Size

Block size for quilting

Finished Sashing Width

Width measurement

Seam Allowance

Seam allowance measurement

Fabric Width

Width measurement

Include Cornerstones

Small squares where sashing strips meet

Fabric Price (optional)

Price per unit

How We Calculate This

Sashing strips run between blocks horizontally and vertically. The calculator counts all strips and works out total fabric.

The formula

Vertical sashing = (Blocks across - 1) × Blocks down

Horizontal sashing = Blocks across × (Blocks down - 1)

Cornerstones = (Blocks across - 1) × (Blocks down - 1)

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.