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.

How to Crochet a Granny Square

A granny square is built from one repeating idea: clusters of three double crochet stitches, separated by chain spaces, worked in rounds outward from the center. Once you understand that the corners get two clusters and the sides get one, you can work a granny square of any size without a pattern in front of you. These instructions use US crochet terms.

What you need

Item	Notes
Worsted-weight yarn	Smooth, light-colored yarn is easiest to learn on — you can see the stitches. One color, or a different color per round.
5.0 mm (H-8) hook	Or whatever your yarn label suggests. Go up a size if your work feels stiff.
Tapestry needle	For weaving in ends. A granny square blanket generates a lot of them.

Step 1: Make the center ring

You have two options, and neither is wrong. Chain four and join with a slip stitch into the first chain to form a small ring — simple, reliable, and leaves a small visible hole in the center. Or use a magic ring, which closes completely and gives a solid center. Beginners usually find the chain-four ring easier for a first square, since you are not fighting a loose loop while learning the cluster rhythm.

Step 2: Round 1 — four clusters, four corners

Chain three (this counts as your first double crochet). Work two more double crochet stitches into the ring, then chain two. That chain-two is your first corner space. Now work three double crochet into the ring, chain two, three more times. You should end with four clusters of three double crochet, separated by four chain-two spaces. Join with a slip stitch to the top of the beginning chain-three.

The square is tiny at this point, and it will look more like a flower than a square. That is correct.

Step 3: Round 2 — learn the corner rule

Slip stitch across into the nearest chain-two corner space. Chain three, then work two double crochet into that same corner space, chain two, and work three more double crochet into the same space. You have just made a corner: two clusters with a chain-two between them, all in one space. That is the rule that makes the square turn.

Chain one, then move to the next corner space and repeat: three double crochet, chain two, three double crochet. Continue around all four corners. Join to the top of the beginning chain. You now have a small square with two clusters per corner and nothing along the sides yet.

Step 4: Round 3 and every round after — the repeating rule

From here the square grows by one identical rule, and every round is the same:

Where you are	What you work
In a corner space (chain-two)	3 dc, chain 2, 3 dc — two clusters sharing one space
In a side space (between clusters)	3 dc — one cluster
Between clusters	Chain 1, or chain 0 for the denser modern look

Each round adds exactly one cluster to every side. Round 3 has one cluster per side, round 4 has two, round 5 has three, and so on. If you ever lose your place, count the clusters along one side and compare it to the others — they should all match.

Step 5: Choosing your size

A granny square grows roughly one inch per round with worsted yarn and a 5.0 mm hook, though your gauge will vary. Six rounds gives you a square of about six inches, the most common size for blanket squares. The calculator above will tell you how many rounds and how many squares you need for a target blanket size, and the square join calculator handles the joining math.

Changing color each round

The classic multicolor granny square changes color every round. Finish the round, fasten off leaving a six-inch tail, then join the new color with a slip stitch into any corner space and begin the next round there. Rotating which corner you start in spreads the joins around the square instead of stacking them all along one edge, which is barely visible in the finished piece but makes for a tidier square.

Every color change creates two ends. A twelve-square blanket at six rounds each is a large number of ends, so weave them in as you finish each square rather than saving them all for the end.

Troubleshooting

Problem	Cause and fix
Square is cupping or curling up	Your tension is too tight, or you are missing chain spaces. Go up a hook size and check that every corner is getting two full clusters.
Corners look rounded, not sharp	Not enough chain in the corner space. Try chain-three corners instead of chain-two with taller yarn.
Sides are wavy or ruffling	You have worked an extra cluster somewhere along a side. Count clusters per side — they must be equal.
Square is not square	Almost always a miscounted corner. Corners take two clusters; sides take one. One corner with a single cluster pulls the whole shape off.
Center hole is too big	Use a magic ring instead of a chain ring, and pull the tail tight before weaving it in.

Blocking and joining

Granny squares rarely come off the hook perfectly square, and this is normal — blocking fixes it. Pin each damp square to its target dimensions on a towel or blocking mat, let it dry fully, and the edges will square up and stay that way. Blocking before joining is worth the wait, because squares that are all the same size join far more easily than squares that are not.

For joining, slip stitch and single crochet joins are the common choices: slip stitch gives a flat, nearly invisible seam, while single crochet leaves a raised ridge that becomes a design feature. Whichever you pick, join every square the same way and in the same direction so the blanket lies flat.

Related Calculators