How Many Granny Squares for a Blanket? (Easy Formula + Examples)

“How many granny squares do I need?” is the first question almost everyone asks before starting a granny square blanket. The honest answer is: it depends on the size of your blanket and the size of your squares. The good news is that the math is simple once you know it.

This guide gives you a quick answer for the most common sizes, then shows you the easy 3-step formula so you can plan any blanket with any square. We also cover how to estimate yarn from a single square, so you buy enough the first time.

What You’ll Need

One blocked test square in your chosen yarn
A measuring tape
A small kitchen or craft scale that weighs in grams
A blocking mat and pins
Your calculator and a notebook

The Quick Answer

Here are the numbers for the three most popular blanket sizes, using common square sizes. Blanket sizes are from Sarah Maker’s crochet blanket size chart. For every size from lovey to king, see our full granny square blanket size chart.

Blanket	Size (inches)	5″ squares	6″ squares	8″ squares
Baby (average)	42 x 52	80 (8 x 10)	63 (7 x 9)	30 (5 x 6)
Small throw	52 x 60	120 (10 x 12)	90 (9 x 10)	48 (6 x 8)
Twin	66 x 90	234 (13 x 18)	165 (11 x 15)	88 (8 x 11)

Numbers are rounded to the nearest whole square and do not include the border.

The 3-Step Formula

Step 1: Measure your blocked square. Measure from one side to the other, not corner to corner. Write it down. Let’s say it is 6 inches.

Step 2: Divide the blanket size by the square size.

Width ÷ square size = squares across
Length ÷ square size = squares down
Round each to the nearest whole number.

Step 3: Multiply. Squares across x squares down = total squares.

That is it. Now let’s try it with real numbers.

Worked Examples

Example 1: A baby blanket with 5-inch squares

You want a baby blanket around 42 x 52 inches, and your test square is 5 inches.

42 ÷ 5 = 8.4, so 8 squares across
52 ÷ 5 = 10.4, so 10 squares down
8 x 10 = 80 squares, for a blanket of about 40 x 50 inches

A 1-inch border all the way around would bring it to about 42 x 52 inches.

Example 2: A throw with 7-inch squares

You want a 50 x 60 inch throw, and your square is 7 inches.

50 ÷ 7 = 7.1, so 7 across
60 ÷ 7 = 8.6, so 9 down
7 x 9 = 63 squares, for about 49 x 63 inches

Example 3: A real pattern

Sarah Maker’s free Granny Square Blanket uses 6-inch squares laid out 6 across and 8 down. That is 6 x 8 = 48 squares, and the finished blanket is about 38 x 50 inches (a lap blanket or small throw) before her single crochet border. It is a nice example of how quickly the math works in practice.

How Much Yarn Will You Need?

Once you know the number of squares, you can estimate yarn from your test square.

Step 1: Weigh your blocked test square in grams.

Step 2: Multiply by the number of squares.

Step 3: Add extra for joining and the border. Many crocheters add 10 to 20 percent, more if you plan a wide border.

Step 4: Divide the total by the grams per skein on your yarn label, and round up.

Example: Your square weighs 12 g and you need 90 squares. 12 x 90 = 1,080 g. Add 15 percent (about 162 g) and you get roughly 1,242 g. If your yarn comes in 198 g skeins, like Red Heart Super Saver solids, that is 1,242 ÷ 198 = 6.3, so buy 7 skeins. If you are using several colors, split this total by how much of each color your square uses.

For a real-world check, Sarah Maker’s 48-square blanket calls for about 1,757 yards of worsted yarn in total, including joining and border. That works out to roughly 36 to 37 yards per 6-inch square when you spread the total over all 48 squares.

How to Plan the Layout

Step 1: Write your grid on paper (for example, 9 across and 10 down).

Step 2: Decide on a color plan: random, diagonal stripes, a checkerboard, or one color per row.

Step 3: As you finish squares, lay them out on a bed or floor in their spots. You will see right away if you need more of one color.

Step 4: Take a photo of the final layout before you start joining.

Common Mistakes (and How to Fix Them)

Planning from a pattern’s square size instead of your own. Your tension may be tighter or looser. Always measure your own blocked square.
Forgetting the border. A wide border can add a few inches to every side. Plan it now so you do not make an extra row of squares you do not need.
Running out of one color. Buy all your yarn at once, with a little extra, so dye lots match.
Mixing yarn brands mid-project. Two worsted yarns can make different-sized squares. Stick to one yarn line if you can.
Not counting as you go. Keep a tally in your notebook or on your phone. It is easy to think you have 60 squares and find you have 54.

Tips

Make a few spare squares. They are handy for swapping out a square that came out too big or too small.
If 200+ squares feels like too many, make bigger squares. Doubling the size of the square cuts the number of squares to about a quarter.
Break the work into a goal, like 2 squares a day. Small daily goals finish big blankets.
Weave in ends after every few squares, not all at the end.
Use the same hook for every square, and keep your hook in the project bag so you do not pick up a different one by mistake.

FAQ

How many granny squares do I need for a throw blanket?
For a common throw size of about 50 x 60 inches, you need roughly 120 five-inch squares, 90 six-inch squares, or 48 eight-inch squares (6 x 8, which gives about 48 x 64 inches). Measure your blocked square first, then use the 3-step formula to get your exact number.

How many granny squares for a baby blanket?
For an average baby blanket of about 42 x 52 inches, you need about 80 five-inch squares or 63 six-inch squares. A smaller stroller blanket of about 30 x 36 inches needs only around 30 six-inch squares, which makes it a great first blanket project.

Is it better to make more small squares or fewer big squares?
Fewer big squares means less joining and fewer ends to weave in. More small squares gives you more room for color play and makes a portable project you can carry anywhere. Both make beautiful blankets, so pick the one you will enjoy making.

Measure one square tonight, do the quick math, and you will know exactly how far you have to go.