A layer cake is 42 ten-inch squares, and ten minus seams is 9½: the quilt math runs on that number. Enter your quilt size; you get the grid, the squares, the cakes to buy, and what the quilt truly finishes at.
Your Quilt
Fine-tune: squares per cake
You Need
1layer cake
42 squares · 6 × 7 grid · finishes 57 × 66.5 in
- Squares needed42
- Cakes of 421 (0 spare)
- Finished size57 × 66.5 in
- Each square finishes9½ × 9½ in
The Formula
squares = (width ÷ repeat) × (length ÷ repeat) · repeat = 9½ + sashing · cakes = ⌈squares ÷ 42⌉A 10 in square sewn on all sides with ¼ in seams finishes at 9½. Sashing stretches the repeat, so fewer squares cover the same bed.
Worked Example
One cake, spent exactly: 42 squares set 6 × 7, edge to edge:
- Finished quilt: 6 × 9½ = 57 in wide, 7 × 9½ = 66½ in long: the one-cake throw, no leftovers.
- The same 57 × 66 target with 1 in sashing: repeat 10½ → 5 × 6 grid, 30 squares, 1 cake with 12 spare for a pieced back or pillow.
- A 66 × 85 twin, edge to edge: 7 × 9 = 63 squares → 2 cakes, 21 spare.
How to Measure Your Inputs
- Quilt size is the finished top. Work from the bed or from the quilt size calculator, then let the grid land near it: layer cake quilts grow in 9½ in steps.
- Sashing is finished width. Cut sashing ½ in wider than you enter here; the sashing calculator prices those strips.
- Counting spares: each 10 in square also slices into four 5 in charms or two 5 × 10 bricks, so spare squares feed borders and pieced backs.
Assumptions and Defaults
- 42 squares per cake; a few collections pack 40, the fine-tune field takes it.
- The grid rounds to whole squares nearest your size, never over by more than half a repeat.
- Squares sewn edge to edge with ¼ in seams; sashing, when entered, runs between squares only. Borders go on top of this math.
Layer Cake Questions, Answered
How big is a layer cake quilt?
A layer cake quilt made from one 42-square cake, sewn 6 × 7 edge to edge, finishes at 57 × 66½ in, a true throw. With 2 in sashing, the same cake reaches about 67 × 78 in, twin size, which is the least expensive size increase in quilting.
How many layer cakes do I need for a queen quilt?
A queen quilt sewn edge to edge needs 9 × 10 = 90 squares for a 90 × 95 in top, which is three layer cakes with 36 squares left over. With 2 in sashing it drops to 8 × 8 = 64 squares, which is two cakes, and the spares can piece an accent strip for the backing.
What can I cut from one 10 inch layer cake square?
One 10 in layer cake square cuts into four 5 in charms, two 5 × 10 in bricks, four 2½ × 10 in strips, or one pair of 9⅞ in HSTs. That flexibility is why a layer cake is the most versatile precut, since every smaller precut fits inside it.
Which costs less, a layer cake or charm packs?
A layer cake and charm packs cost about the same per square inch, but the layer cake is the better buy when your pattern needs pieces larger than 5 in, because charms can’t be made bigger. Count your pattern’s piece sizes first, then buy the precut that cuts them without waste.