How Many Granny Squares Do You Need for a Blanket?

A granny-square blanket starts with two measurements: the finished blanket size you want and the finished size of one square. From there, you can choose a grid that is close to your target dimensions and adjust it for joins, a border, or a different layout.

Measure a finished square first

Make, block, and measure one representative square before committing to a full grid. Measure the square the way it will sit in the finished blanket. Joining methods, blocking, and border choices can all change the final dimensions a little.

Calculate columns and rows

Divide the usable blanket width by the finished square width to estimate columns. Divide the usable blanket length by the finished square height to estimate rows. Round to whole squares, then multiply columns by rows for the total number of squares.

Allow for joins and borders

A flat join can take up a little width, while a decorative join may add it. A border adds to the outside dimensions rather than changing the number of squares. Make a small joined sample when exact sizing matters, particularly if you are matching a bed, sofa, or recipient’s preferred blanket size.

Estimate yarn after the grid is set

Once you know the square count, weigh or measure the yarn used by one representative square. Multiply that amount by the number of squares, then include yarn for joins, a border, colour changes, and a safety margin. Keep the estimate separate for each colour if the layout uses multiple shades.