Granny Square Calculator

A note on join thickness

This calculates squares edge-to-edge with no allowance for join bulk. A whip-stitch or flat slip-stitch join adds almost no width; a bulkier join (like a surface crochet seam or a chunky join-as-you-go round) can shave a small amount off the finished size across many squares — usually only fractions of an inch per join, but that adds up across a 6-column layout. If you're using a thicker join, crochet and join a 2×2 test swatch first and measure that instead of trusting the single-square size alone.

Standard blanket sizes, if you're not sure what to target

A lapghan or stroller blanket usually finishes around 30 by 40 inches; a throw for a couch runs 50 by 60; a twin bed topper is roughly 66 by 90; queen and king coverlets run 90 by 90 and up. These aren't hard rules — crocheted blankets are typically a bit more forgiving on exact dimensions than woven ones — but they're a reasonable target if you're building from squares rather than working top-down from a body measurement.

Blocking each square to a consistent size before joining makes a bigger difference to the final look than most beginners expect. Squares crocheted in the same yarn and hook can still come out slightly different sizes depending on where in a project they were made — tension often loosens slightly as a crocheter gets further into a repetitive project — and wet-blocking every square to the same pinned dimensions before assembly evens that out.