How quilt size is calculated
Work with finished sizes (what shows in the quilt, without seam allowances):
width = blocks across × block size + sashing strips × sashing width + 2 × border width
With sashing between blocks only, there is one fewer sashing strip than blocks in each row. With sashing around the outside too, there is one more.
Example
Thirty 12" blocks in a 5 × 6 layout with no sashing and a 4" border make a 68" × 80" quilt, a comfortable lap or twin-top size.
Planning tips
- Decide how far the quilt should hang over the bed sides (the "drop") before choosing the layout; measure the mattress rather than relying on a generic size chart.
- Quilting shrinks a quilt slightly, often by a few percent depending on batting and density. Plan a little extra if the size is critical.
- Use the backing and binding calculators once you know the finished size.
Frequently asked questions
How many 12-inch blocks for a queen quilt?
It depends on your mattress and how much drop you want. For example, a 7 × 8 layout of 12" blocks with a 6" border gives 96" × 108", a common queen size. Enter your own layout above.
Do I include seam allowances?
No. Use finished sizes for blocks, sashing and borders. Seam allowances are only added when cutting.