Crochet reference

Crochet hook for granny squares

There is no one granny square hook. The yarn picks the hook, and then you get a say. Here is what 20 real patterns use, how big the same square comes out at four hook sizes, and how to get a whole stack of squares to match.

The yarn decides

Start with the hook size on your yarn label or in your pattern.

Worsted: 5 or 5.5 mm

That is what the worsted patterns we read used most, an H-8 or I-9. DK patterns used 4 mm, a G-6.

One hook per blanket

Pick it, then keep it in the project bag so every square matches.

What size

What size hook for a granny square?

We read 20 free granny square patterns and tutorials and wrote down the yarn and hook in each. Here is what they use, next to the Craft Yarn Council's general range for that yarn.

Your yarn	The patterns we read	Craft Yarn Council
DK (3)	4 mm (G-6) in all five DK patterns we read	4.5 to 5.5 mm
Worsted or aran (4)	5 mm (H-8) or 5.5 mm (I-9) most often; some as small as 4 mm or as big as 6.5 mm	5.5 to 6.5 mm
Bulky (5)	8 mm (L-11) in the one bulky pattern we read	6.5 to 9 mm
Crochet thread	None of the 20 was a thread granny. For thread and steel hooks, see the hook size chart.	Steel 1.4 to 1.6 mm, or a 2.25 mm hook, for lace weight and fine thread

Notice something? The DK and worsted patterns we read sit at or under the Council's range. The Council calls its numbers guidelines only, and both are fine places to start. Not sure what an H or an I is in millimeters? See the crochet hook size chart.

Should you go down a size?

One teacher says yes. That teacher made the same square twice in the same yarn, once with a 5.5 mm hook and once with a 5 mm, and found the 5 mm square neater, with less lean. That teacher now uses a hook one or two sizes smaller than the label.

Others say go up for a blanket. A hook maker's guide suggests a slightly larger hook for a softer square with more drape, and a smaller one for a firm bag. Both are ways to get a look you like. It is your square.

Four hooks

The same granny square at four hook sizes

Our Classic Granny Square, four rounds and a border in medium yarn. Krowshea worked out each size from the usual gauge for that hook, and the squares are drawn to scale.

**6.5 mm** K-10 1/2
about 6 1/4 in (16 cm)

Each size in this table is about half an inch bigger than the one before. That is not much on one square. It adds up fast across a blanket:

Hook	One square (estimated)	For a 50 × 60 in throw
4 mm (G-6)	4 3/4 in 12 cm	143 squares 11 × 13
5 mm (H-8)	5 1/4 in 13.5 cm	120 squares 10 × 12
5.5 mm (I-9)	5 3/4 in 14.5 cm	99 squares 9 × 11
6.5 mm (K-10 1/2)	6 1/4 in 16 cm	80 squares 8 × 10

Estimates at the usual gauge for each hook, before joining and blocking. Your hands set the real size: our own square, made in yarn with the 5.5 mm hook, came out 5 1/4 in, half an inch smaller than the estimate. One maker who measured a daisy granny in worsted got 4, 4 1/2 and 4 3/4 in with 3, 4 and 5 mm hooks.

What changes when you change the hook

Go smaller. The square gets smaller, firmer and denser. Go too small and it turns stiff and hard to work into.
Go larger. The square gets bigger, softer and more open, with more drape. Go too large and it turns floppy, with wide spaces between the stitches.

Try it: three squares

The label hookMake one square with the hook on your yarn label.
One each sideMake one a size smaller and one a size larger. Same yarn, same rounds.
CompareLay them side by side. Measure them. Fold them. Hold one up by a corner.
Keep oneKeep the one you like. That is your hook.

Lying flat

If your granny square will not lie flat

Count first. A missed corner or an extra chain does this more often than the hook does. Our pattern lists the count for every round, so you can check. If the count is right, look at the hook.

It cups like a bowl. Your stitches are too tight for the yarn. Go up a hook size, or half a size, and try again.
It ruffles. Your stitches are too loose for the yarn. Go down a size.
It looks more like a circle. Too many chains on the sides. Chain 1 along the sides and chain 2 at the corners.
It leans or twists. Normal when you never turn your work. Turning the square over after each round helps, a smaller hook can help, and blocking straightens it.
The sides are a bit wavy. Also normal off the hook. Block it.

Matching squares

Making granny squares match for a blanket

One yarn weight. Squares in different weights come out different sizes. Even two yarns of the same weight can differ, so watch the first few.
One hook. Use the same hook for every square and keep it with the project.
Measure the first square. Write its size down and check new squares against it as you go.
Block, then measure. Most teachers block each square before joining, pinned to the same size. Some block the finished blanket instead.

Still have a few odd ones?

A little small. Block it out to size.
A lot small. Add one more round. In one designer's hands, single crochet adds a little and double crochet adds more.
Too big. Take out the last round, then work it again in a shorter stitch, or leave it off.

Cotton or acrylic

Use the hook on the label either way; no source we read gives cotton its own hook rule. Acrylic is a common blanket yarn. It blocks, then slowly relaxes again. Cotton holds its shape and is a usual pick for bags, and one shop's granny dishcloth uses it too. Blocking acrylic with steam is argued about: some teachers swear by it, and one guide says steam is not suitable for acrylic. If you try it, keep the heat off the yarn and test a scrap first.

Does the kind of hook matter?

For granny squares, not in any way we could find. No one we read says an inline or a tapered head makes a better granny. Use the hook your hand likes, and if you are still choosing, see choosing a crochet hook.

Questions

What size crochet hook is best for granny squares?

The one that suits your yarn. In the patterns we read, worsted (medium, 4) grannies most often use 5 mm (H-8) or 5.5 mm (I-9), and DK grannies use 4 mm (G-6). Start with the hook on your yarn label or pattern.

Is a 5 mm hook good for granny squares?

Yes, with worsted or aran yarn. It was one of the two most common hooks in the worsted patterns we read.

What hook for DK granny squares?

4 mm (G-6) in every DK pattern we read. The Craft Yarn Council's general range for DK yarn is 4.5 to 5.5 mm.

Should I go up or down a hook size for granny squares?

Down for a neater, firmer square. Up for a softer, more open one. Teachers disagree on which is better, so make one of each and look.

Why are my granny squares different sizes?

Tension changes from day to day, and two yarns of the same weight can differ. So can two hooks marked the same size. Measure your first square, keep one hook for the project, and block to size. Most teachers block before joining.

Why does my granny square cup or ruffle?

Count the stitches and chains first. If the count is right, a square that cups like a bowl is too tight for the yarn, so go up a hook size. A square that ruffles is too loose, so go down a size.

Why does my granny square twist?

Working every round from the same side makes it lean. Turning the square over each round helps, a smaller hook can help, and blocking straightens it.

Should I measure granny squares before or after blocking?

After. Blocking makes a square larger.

Sources

Where this comes from

Read November 12, 2026. Where sources disagree, we say so. The four-hook sizes are Krowshea's estimates; the pattern survey is our own count of the pages below.

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