How Many Quilt Blocks Do I Need? (Calculator)
Enter the size you want the quilt to be and the finished size of your blocks (the size after they are sewn in, not the cut size). The calculator rounds up to whole blocks and tells you the size you will actually end up with.
How it works
- Take off the border: the blocks must cover the width minus 2 × border, and the length minus 2 × border.
- Blocks across = that width ÷ block size, rounded up. Blocks down = that length ÷ block size, rounded up.
- Total blocks = across × down.
- Actual size = blocks across × block size + 2 × border, and the same for the length.
Examples
- Queen, 84 × 91.5 in, 12 in blocks, no border. 84 ÷ 12 = 7 across. 91.5 ÷ 12 = 7.6, round up to 8 down. 56 blocks, and the quilt finishes at 84 × 96 in.
- 60 × 72 in throw, 10 in blocks, 4 in border. The blocks cover 52 × 64 in: 5.2 → 6 across, 6.4 → 7 down. 42 blocks, and the quilt finishes at 68 × 78 in.
- Twin, 62.5 × 86.5 in, 8 in blocks, no border. 7.8 → 8 across, 10.8 → 11 down. 88 blocks, finishing at 64 × 88 in.
The 84 × 91.5 and 62.5 × 86.5 sizes come from the quilt size calculator with a 12 in drop.
When the rounding is too much
Rounding up can add several inches. Ways to get closer to the target:
- Change the block size and try again: the calculator shows the new finished size immediately.
- Use a border to make up the difference instead of a whole extra row of blocks.
- Round down instead if a slightly smaller quilt is fine: one fewer row or column.
Next steps
With the finished size settled, work out the backing and binding.
Sources
- Computed with the formulas above.