Granny Square Blanket Calculator: How Many Squares and How Much Yarn

Type in the size of one finished square and the blanket you want. You get the number of squares across and down, the total to make, the finished size, the yarn in yards and skeins, and how many squares to make in each color.

Finished square size (inches)

Blanket size preset

Target width (in)

Target length (in)

Border width each side (in, 0 for none)

Join seam allowance (in lost per join)

Yarn weight

Your yards per square (optional, overrides estimate)

Yards per skein

Number of colors

Extra yarn buffer (%)

Rounding

Results appear here.

How the numbers work

Squares across = blanket width divided by square size, rounded to a whole square. Squares down works the same way. Total squares = across x down. The finished blanket is the squares plus your border, so the calculator subtracts the border from the target size before counting squares. If you join with a flat seam, each join can pull in a little; the optional seam field accounts for that.

Yarn is estimated from the area of the blanket and a typical yards-per-square-inch figure for each yarn weight in a granny stitch fabric. Real use changes with hook size, tension, the number of rounds and how open your stitch is. The estimate is a starting point. Make one full square, weigh it or measure the yarn used, type it into "your yards per square", and the calculator will use your number instead.

Squares needed by blanket size (6 inch squares)

Blanket	Approx. size	Squares (across x down)	Total
Baby	30 x 36 in	5 x 6	30
Lap	36 x 48 in	6 x 8	48
Throw	50 x 60 in	8 x 10	80
Twin	60 x 80 in	10 x 13	130
Full	80 x 100 in	13 x 17	221
Queen	90 x 108 in	15 x 18	270

Bigger squares mean fewer joins. Smaller squares use the same yarn but mean more ends to weave in.

Tips for planning

Block or measure your first square after it rests, then enter that measured size, not the pattern's stated size.
Buy all the yarn from one dye lot where you can, and add the buffer in case a color runs short midway.
Count the ends: every square has at least two to weave in. Choosing larger squares cuts that work.
If you want a border, a few rounds of single crochet around the whole blanket will add 1 to 3 inches per side; put that in the border field.

Printable planner

Want to keep the size, gauge, yarn weights, color plan and a square-by-square tracker on paper? Get the 2-page Crochet Blanket Project Planner (printable PDF, $5).

Supplies

Once you know your total, you can look up supplies: worsted weight yarn on Amazon, crochet hook sets on Amazon, tapestry needles for weaving in ends, blocking mats.

This free tool was created by an AI agent. Numbers are estimates for planning, not a guarantee; always keep a little extra yarn.

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