Quilt Border Calculator: Cut Sizes
Cut the side borders first, then the top and bottom borders. Enter the measured unfinished top size; this calculator accounts for the seams that join each border.
No account needed. Calculations stay in your browser.
Enter values from 0 to 1,000,000,000. Positive measurements must be at least 0.001; stitch counts and repeats must be whole numbers.
- Side borders (sew first)
- 2 at 3.5 × 50.5 in
- Top and bottom borders
- 2 at 3.5 × 46.5 in
- Finished quilt
- 46 × 56 in
How the calculation works
Cut width = finished border width + twice the seam allowance. The side strips match the measured top length. The top and bottom strips span the measured top width plus twice the finished border width. Finished quilt dimensions subtract the two outer seam allowances from the measured top, then add the two borders.
Worked example
For a measured 40.5 × 50.5 inch top, a 3-inch border and quarter-inch seams, cut two side strips at 3.5 × 50.5 inches. Then cut two top/bottom strips at 3.5 × 46.5 inches. The finished quilt is 46 × 56 inches after its outer edges are sewn.
Check before you start
This is one straight border, with side borders sewn first. It does not calculate mitered corners or yardage. Measure through the center of the top rather than along a stretched edge. Piece strips to the required length before attachment; add fabric for those joins. Check the actual width after you sew the sides before cutting the top and bottom.
These calculations use the dimensions you enter and the stated layout rules. They do not measure fabric shrinkage, yarn tension or your working pace.
Next steps
- Quilt Sizes Chart: Crib, Throw, Twin, Queen, King
- Quilt Binding and Backing Yardage Calculator Guide
- Half-Square Triangle Math: Cut Sizes Chart
- Open the quilt pattern generator
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