QuickCheckTools

Quilt block calculator

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Choose the quilt size you want and your block size. You'll see how many blocks across and down, the total, the finished size, and the sashing to cut.

Worked example

A twin quilt about 72" × 90" with 15½" blocks, 2" sashing and a 2" border (Utah State University Extension's published T-shirt quilt):

  1. Across: (72 − 4 + 2) ÷ (15½ + 2) = 4 blocks. Down: (90 − 4 + 2) ÷ 17½ = 5.03, so 5 blocks.
  2. Total: 4 × 5 = 20 blocks.
  3. Centre: 4 × 15½ + 3 × 2 = 68" wide; 5 × 15½ + 4 × 2 = 85½" long. With the border: 72" × 89½".

Questions

How many quilt blocks do I need?

Take the width you want, subtract the borders, add one sashing width, and divide by the block size plus the sashing. Round to the nearest whole number for blocks across, and do the same for the length. Multiply the two for the total.

How many 12" blocks for a queen quilt?

A queen quilt of about 90" × 95" needs 8 × 8 = 64 blocks of 12" with no sashing or borders, which makes 96" × 96". Seven across makes 84"; add borders to reach the size you want with fewer blocks.

How many blocks for a throw or lap quilt?

A 60" × 72" lap quilt takes 30 blocks of 12": 5 across and 6 down. A 50" × 65" throw (Missouri Star's size) takes 4 across and 5 down with 12" blocks and a few inches of border.

What size should sashing be?

Sashing is usually 1" to 3" finished. Cut it ½" wider than it finishes. The calculator lists the short strips between blocks, the long strips between rows, and the cornerstones if you use them.

What sizes are standard quilts?

These presets use Missouri Star Quilt Co.'s chart: crib 36" × 52", throw 50" × 65", twin 68" × 86", full 84" × 90", queen 90" × 95", king 108" × 95", California king 102" × 100". Mattresses and overhangs vary, so check your bed.

Why isn't my quilt exactly the size I asked for?

You can only use whole blocks, so the calculator picks the nearest number of blocks and shows the size it actually makes. Adjust the border width to land exactly on your target.

Sashing runs between blocks; use the border for an outer frame. Checked against Utah State University Extension and C&T Publishing's layouts and Missouri Star Quilt Co.'s standard sizes.