Granny Square Calculator — How Many Squares Do You Need?

The number of granny squares for a blanket depends on two things: the finished size of each square after blocking, and the size of the blanket you want. The formula is straightforward — divide the blanket width by the square size to get squares across, divide the blanket height by the square size to get squares down, and multiply for the total. The joining method affects the result because each join adds a small amount to the overall width.

For a typical throw blanket (48×60 inches) made with 6-inch squares and no joining width, you need 8 squares across and 10 squares down — 80 total. For the same blanket with a flat seam join that adds 0.25 inches between squares, the effective square size increases slightly and the count adjusts accordingly. The calculator above handles this automatically.

Square size must be measured from your actual blocked squares, not from the pattern description. Granny squares grow when blocked, and the amount of growth depends on fiber content, hook size, and how aggressively you block. Always make and block a test square before calculating the full project count.

Common blanket sizes and approximate square counts at the most popular finished square sizes. Baby blanket (36×45 inches): at 6-inch squares, 6×8 = 48 squares. At 9-inch squares, 4×5 = 20 squares. Lap blanket (40×50 inches): at 6-inch squares, 7×9 = 63 squares. At 8-inch squares, 5×7 = 35 squares. Throw (48×60 inches): at 6-inch squares, 8×10 = 80 squares. At 12-inch squares, 4×5 = 20 squares. Full/double (60×80 inches): at 6-inch squares, 10×14 = 140 squares. At 8-inch squares, 8×10 = 80 squares.

These counts assume no joining width. If you use a flat seam, single crochet join, or any method that adds width between squares, use the calculator above with your actual joining width to get an exact count. A 0.25-inch join across 10 squares adds 2.25 inches to the final width — enough to shift the count by one square in each direction on a large blanket.

For garments like cardigans, the same calculator applies. Enter the finished panel width as the blanket width and the panel height as the blanket height to find how many squares fit across and down. Most granny square cardigan patterns use 4–6 inch squares arranged in rectangles for body panels, with smaller squares or half-squares for shaping.