Disclaimer

The cutting charts and calculators on Quilt Block Atlas are computed by one shared set of functions and checked by the site's own tests. They cannot see your fabric, your seam or your pressing. Cut one piece of each size and measure it before you cut the rest.

Your sewing decides the result

Every chart assumes the seam allowance it states, sewn accurately. A seam that runs a little wide or narrow, pressing that stretches a bias edge, or fabric that shifts under the ruler all change the finished size, and no chart can measure them for you.

If a sewn row comes out short, the quarter inch seam allowance test shows how far your seam is off. If a block is a little large, the guide to squaring up a quilt block gives the size to trim to.

Conventions, not rules

Some cutting sizes are quilting conventions rather than exact geometry. The triangle add-ons here are the conventional ones: the exact figure, rounded up to a mark on your ruler. Some published charts add extra trimming room on top of them, so another chart can list a larger starting size for the same finished unit. Where quilters disagree, such as how much to oversize a triangle before trimming it, the site shows the published ranges with each source named and does not choose one for you.

If you are following a pattern from a book, magazine or designer, follow its cutting list where it differs from this site. Its designer usually matched the sizes to their own seam and trimming instructions.

Printing a chart does not change its numbers, but a printed template is only the right size if your printer did not resize the page. The guide to printing quilt patterns at 100% shows how to check. The fabric yardage calculator gives an estimate rounded up, for the usable width it states. Buy extra if you prewash, fussy-cut or match a print.

Rotary cutter safety

A rotary cutter blade is very sharp. Close the blade guard every time you put the cutter down. Cut away from your body, and keep the fingers of your ruler hand back from the edge. Store cutters and spare blades out of reach of children. Follow the safety instructions that came with your cutter; this site gives measurements, not safety training.

Liability

Quilt Block Atlas is free. What it does and does not guarantee, and who is responsible for a cut, are set out in the terms of use.

Ads and outside links

Quilt Block Atlas does not show ads today. If it does in future, Google will serve them: the site will not pick individual ads, and an ad will not be a recommendation. The privacy policy explains what Google receives.

Links to other websites go to the sources named in block histories, and the privacy policy links Google's ad settings. The site does not control those pages. It has no affiliate links, and a link is not an endorsement.

Report a mistake

If a number looks wrong, send the block, the finished size and the piece you measured. The contact page has the address and explains why those three details are enough to check it.