Granny Square Blanket Calculator

Free calculator for how many granny squares you need for any blanket size — baby to king — by your square size, with the grid layout, finished dimensions, a worsted yarn estimate, and a yarn budget from your skein price.

Quick answer

For a 90×100 inch queen blanket you need 255 six-inch granny squares (15 across × 17 down); a 30×36 inch baby blanket takes 42 five-inch squares (6 × 7). Bigger squares mean far fewer to crochet and join — enter your blanket size and your square’s real blocked size and the calculator returns the exact grid, finished dimensions, and a worsted yarn estimate.

Blanket Size

Width (inches)

Length (inches)

Square size (inches)

Units

Measure one finished, blocked square — a classic 5-round granny square in worsted weight usually lands around 5 inches (12.5 cm).

You Need

120

squares

10 × 12

across × down

50×60

finished inches

~2,970

yards worsted (~15 skeins)

Price per skeinenter your skein price for a yarn budget

Layout preview

The yarn estimate above assumes worsted-weight granny stitch — chunkier yarn, denser stitches, or generous borders need more, so buy an extra skein of each color.

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How to plan a granny square blanket

Five steps, and the second one decides whether the other four are right.

Start from a size
Nine standard blanket sizes are preset, from a 12-inch lovey to a 108-inch king. Pick the nearest one, or type your own width and length — anything from 6 to 150 inches, in inches or centimetres.
Measure one finished square and enter that
Not the size you meant to make: the size you actually made, between 2 and 15 inches. Everything downstream is a multiple of this number, so an eighth of an inch of gauge drift becomes several inches across a throw. Block one square, measure it, use that.
Read the grid, and check the finished size against your target
The calculator snaps your target to the nearest whole number of squares each way, which means the finished blanket can land slightly under the size you asked for as well as over. The finished measurement it reports is the real one, so trust that rather than what you typed.
Take the yarn total to the shop
The estimate works from about 0.86 yards of worsted-weight granny stitch per square inch of finished fabric, adds 15% for joining and a border, rounds to the nearest 10 yards, and converts the total into whole 200-yard skeins. Chunkier yarn, denser stitches or a wide border all need more than it says.
Type the price on the label to budget the project
The price per skein multiplies straight through the whole-skein count, in whatever currency you typed. The tool does no conversion.

Plan the Whole Blanket Before Square One

Granny square blankets fail in the planning, not the crocheting: you fall in love with a palette, make forty squares, and discover you need a hundred and forty. This calculator works the problem from the finished blanket backwards — pick a standard size or enter your own, tell it how big one of your squares blocks, and it returns the exact grid, the true finished dimensions once squares snap to whole counts, and an honest worsted-weight yarn estimate.

The single most important input is your real square size. Gauge varies enough between crocheters that the same pattern blocks anywhere from 4.5 to 5.5 inches — and across a queen blanket that half inch is the difference between 255 squares and 340. Make one square, block it, measure it, then plan.

Squares Needed by Blanket Size

How many granny squares for every common blanket size

Blanket	4″ squares	5″ squares	6″ squares	8″ squares
Lovey (12″ × 12″)	9	4	4	4
Baby / Stroller (30″ × 36″)	72	42	30	20
Lapghan (36″ × 48″)	108	70	48	30
Crib (45″ × 60″)	165	108	80	48
Throw (48″ × 60″)	180	120	80	48
Twin (66″ × 90″)	391	234	165	88
Full / Double (80″ × 90″)	460	288	195	110
Queen (90″ × 100″)	575	360	255	143
King (108″ × 100″)	675	440	306	182

Counts snap each dimension to the nearest whole square — the calculator above shows the resulting finished size for your exact numbers.

Joining Strategy Changes the Math

Join-as-you-go adds a small border to every square, effectively growing them a quarter to half inch — measure a joined pair, not a lone square, if that is your method. Whip-stitched or mattress seams add almost nothing. And if your blanket needs a few extra inches, a border is cheaper than another row of squares: two or three rounds of granny stitch around the assembled blanket adds width fast and frames the whole project. Pair this planner with our granny square pattern generator to choose the colors once you know how many squares you are making.

The yarn estimate here covers a granny-square blanket in worsted weight. Working a different stitch, a different yarn weight, or one solid piece instead of squares? The crochet yarn calculator answers how much yarn you need for a blanket across every stitch from single crochet to granny, sock weight to super bulky.

Frequently Asked Questions

How many granny squares do I need for a queen size blanket?

For a 90 × 100 inch queen blanket you need 255 six-inch squares (15 across × 17 down), or 360 five-inch squares (18 × 20). Larger squares mean far fewer to crochet and join — the calculator shows the exact count for your square size.

How many granny squares for a baby blanket?

A 30 × 36 inch baby blanket takes 42 five-inch squares (6 across × 7 down) or 30 six-inch squares (5 × 6). It is the classic first granny square project: small enough to finish, big enough to learn joining.

What size is a granny square?

Whatever you make it — but a classic 5-round granny square in worsted weight with a 5.0 mm hook typically blocks to about 5 inches (12.5 cm). Always measure your own finished, blocked square and feed that number into the calculator; a half-inch difference changes a queen blanket by dozens of squares.

How much yarn do granny square blankets use?

Rough worsted-weight guide: a baby blanket runs about 1,000 yards, a throw 2,800–3,300 yards, and a queen 9,000+ yards. The calculator estimates yards and ~200-yard skeins for your exact size, including about 15% extra for joining and a border — chunky yarn or dense joins need more.

How much will the yarn for my blanket cost?

Type the price from your skein label into the “Price per skein” box and the calculator multiplies it by the whole skeins your blanket needs — a 14-skein throw at 4.99 a skein budgets to about 69.86, in whatever currency you typed. Handy before you commit to a colorway at the yarn shop.

Should I count the border and joining in the size?

Yes — joining adds roughly a quarter inch per seam depending on your method, and a border adds 1–3 inches all around. The safest approach: plan with the calculator, then stop adding rounds of border when the blanket hits your target measurement.

Granny square blanket calculator showing a queen-size layout grid with square count and yarn totals — Pick a blanket size and square size — the grid, square count, and yarn estimate update instantly.