Formula
Width is the mattress plus a drop on both sides. Length is the mattress plus one drop at the foot and the pillow tuck at the head. That length split is a planning choice: the foot hangs, the head covers pillows.
quilt width = mattress width + 2 × drop
quilt length = mattress length + drop + tuck
blocks = floor(quilt ÷ block)
border = (quilt − blocks × block) / 2
Only whole blocks are counted. The leftover, split in half, is the suggested border. A drop of 14 inches is the starting value on this page; it is not a standard mattress dimension.
Worked examples
Queen, 14 in drop, 10 in tuck, 12 in blocks. 60 + 28 = 88 in wide. 80 + 14 + 10 = 104 in long. Seven blocks across leave 4 in, so 2 in of border each side. Eight blocks down leave 8 in, so 4 in of border each end.
Twin, same drop and tuck. 38 + 28 = 66 in wide and 75 + 14 + 10 = 99 in long. At a 12 in block that is 5 across and 8 down, with 3 in left on the width and 1.5 in on each end.
Crib, 8 in drop, no tuck, 6 in blocks. 28 + 16 = 44 in by 52 + 8 = 60 in. Seven blocks across and ten down fill it with a 1 in side border and no end border.
Reference
Mattress sizes used by the presets. Drop, tuck, and block are not part of the mattress.
| Mattress | Width | Length | Quilt at 14 in drop, 10 in tuck |
|---|---|---|---|
| Crib | 28 in | 52 in | 56 × 76 in |
| Twin | 38 in | 75 in | 66 × 99 in |
| Twin XL | 38 in | 80 in | 66 × 104 in |
| Full | 54 in | 75 in | 82 × 99 in |
| Queen | 60 in | 80 in | 88 × 104 in |
| King | 76 in | 80 in | 104 × 104 in |
| Cal king | 72 in | 84 in | 100 × 108 in |
Questions
How big is a quilt for a queen with a 14 inch drop?
A 60 by 80 inch queen plus 14 inches of drop on both sides is 88 inches wide. Length is the mattress plus one drop at the foot and a 10 inch pillow tuck, which is 104 inches. Twelve-inch blocks give 7 across and 8 down, with 2 inches left on each side and 4 inches at each end.
Why is the drop counted once on the length?
The side drops hang off both edges, so the width gains two drops. The foot gets one drop. The head is the pillow tuck, which covers the pillows instead of hanging like the foot. Change the tuck if you want the quilt to stop at the mattress.
What is the suggested border?
Blocks are kept whole. Half of whatever is left after the blocks is the border on that edge. A queen at these defaults wants about 2 inches on the sides and 4 inches on the ends. The border calculator takes that width and turns it into strips.
Sources
- Mattress presets: crib 28×52, twin 38×75, twin XL 38×80, full 54×75, queen 60×80, king 76×80, Cal king 72×84 inches.
- Finished size = width + two drops, length + one drop + pillow tuck. Whole blocks; leftover ÷ 2 is the border. The 14 in drop default is a planning value, not a published bed standard.