Quilt Size Calculator
See what finished size your block grid will produce, and compare it to standard bed quilt sizes.
Tip: use URL parameters, e.g. ?blockSize=12&blocksAcross=5&blocksDown=6.
Standard quilt sizes (approximate, US)
- Crib: 36" × 52" (baby blanket)
- Twin: 68" × 88" (with 12" drop)
- Full/Double: 80" × 88"
- Queen: 88" × 96"
- King: 104" × 96"
- Throw/Lap: 50" × 65"
How to use the size calculator
Multiply your finished block size by the number of blocks in each direction. A 12" block laid out 5 across and 6 down gives a 60" × 72" top — right in the sweet spot for a throw quilt.
Remember: these are the quilt top dimensions. You'll add borders if you want them bigger, and the backing/batting will be larger still (see our backing and batting calculators).
What each input means
- Finished block size (inches) — the block size after seams are sewn. Most patterns state this explicitly: a block cut at 12.5" finishes at 12". Enter the finished number.
- Blocks across — how many blocks sit side by side in each row.
- Blocks down — how many rows of blocks you have.
The result is the quilt top size only. It doesn't include sashing, borders, binding or the extra margin needed for backing and batting, so use it as the starting point for planning, then adjust with the related tools.
When to use it. Use this calculator whenever you're planning a quilt from a block grid: it turns a layout into a finished size you can compare against standard quilt sizes and your mattress. It's the natural first step of planning, before you buy fabric or cut a single piece. If the number lands between standard sizes, you have two options — change the grid by adding or removing a row of blocks, or plan to adjust with borders. The calculator is also a good way to understand how block size and grid interact: doubling the block size quadruples the fabric area even though the number of blocks stays the same, so the choice of block size has a big effect on both yardage and the finished look. When shopping for a pattern, compare this number against the pattern's stated finished size, since covers often list the block grid rather than the final dimensions. If the quilt is for a bed, decide the drop you want before choosing the grid, since standard size charts assume different mattress depths.
Common mistakes to avoid
- Entering the cut size instead of the finished size. A 12.5" cut block entered as 12.5" will overstate the quilt by half an inch per block.
- Forgetting sashing. Three-inch sashing between five blocks adds 12 inches across; the quilt size changes significantly.
- Ignoring borders. Borders add width and length on top of the block grid, so plan the top size first and add borders deliberately.
- Treating standard sizes as gospel. Bedding sizes vary by brand and by how much drop you want, so compare your target against your mattress and preference.
- Measuring a pieced top before it's pressed. Seams and blocks can distort; measure the actual top after pressing, not the ideal grid.
Frequently asked questions
What's the standard size for a throw quilt?
About 50" × 65" is a typical lap/throw size. A 12" block in a 4 × 5 grid gives 48" × 60", which works well.
How many 12-inch blocks for a queen quilt?
A queen top is roughly 88" × 96", so you'd need a 7 × 8 grid = 56 blocks of 12" finished size.
Does sashing change the finished size?
Yes — sashing adds width between blocks. Use our sashing calculator to account for it, or add the sashing width to your block grid.
Should I size my quilt before or after borders?
Plan the top size first (blocks ± sashing), then decide borders to reach your target mattress size.