Crafts & Making
Quilt Calculator
Estimate block counts and block fabric from a quilt grid and cut patch size.
Enter your measurements
Results update as you type.
About this calculator
Enter the quilt grid — rows and columns of identical blocks — the finished block size, the seam allowance per edge and the usable bolt width. The calculator reports the finished top size, the cut patch size including seams, and the fabric length needed for the blocks in straight rows. Borders, backing, batting and binding are separate.
How to measure
- Enter the rows and columns of identical finished blocks.
- Add seam allowance per edge and enter usable fabric width.
- The estimate covers simple rectangular block patches only; borders, backing, batting and binding are separate.
How to use this calculator
- Choose the rows and columns of blocks.
- Measure the finished block size.
- Set the seam allowance per edge — ¼ in is typical.
- Enter the usable bolt width.
- Calculate; add borders, backing, batting and binding separately.
Formula
Blocks = rows × columns
Finished top = columns × block width by rows × block height
Cut patch = finished block + 2 × seam on each dimension
Patches per bolt row = ⌊bolt width ÷ cut patch width⌋
Block fabric length = ⌈blocks ÷ patches per row⌉ × cut patch height
Assumptions
- All blocks are identical rectangles cut from the same fabric.
- Patches are laid in straight rows without rotation or nesting.
- Seam allowance is added on both edges of each dimension.
Common mistakes
- Entering cut block dimensions where finished dimensions are requested.
- Adding seam allowance twice.
- Assuming block fabric includes borders, binding, batting and backing.
Worked example
Try it: press “Load example” above the form.
20 blocks of 6½ in cut size fit 6 per 42 in bolt row; 4 rows × 6½ in needs 26 in of block fabric.
Limitations
No piecing pattern, fabric prewash shrinkage, directional print matching or long-arm quilting estimate. Block fabric only.
Frequently asked questions
Are block dimensions finished or cut?
Use finished block dimensions and the seam allowance requested by the form. The calculator adds seam allowances to obtain the cut size.
Does it include backing, binding and borders?
Only the stated block-fabric model is included. Backing, batting, binding, sashing, borders and directional matching require their own quantities.
What does the worked example show?
20 blocks of 6½ in cut size fit 6 per 42 in bolt row; 4 rows × 6½ in needs 26 in of block fabric.
Which assumptions should I check before using the result?
No piecing pattern, fabric prewash shrinkage, directional print matching or long-arm quilting estimate. Block fabric only.
Sources
Sources explain the methods and any named product presets. Check your product label where coverage, yield or density differs.
- Omni: quilt binding
Perimeter and straight-strip workflow. The explicit joining-loss model and single-block quilt model are defined on this page.
- Sailrite: fabric calculator
Usable width and fabric layout context. Rug envelopes are the stated rectangle geometry, not a recommended clearance.
Calculation documentation · Updated 2026-11-08 · Version 1.6.4. Estimates are planning aids. Confirm quantities, coverage and prices with your supplier before purchasing. Found an error? Report it.
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