Loom Mosaic

Quilt block designer & quilting calculators

Quilt size calculator

What size should my quilt be?

Start from the mattress, add the drop over the sides and a pillow tuck, then see how many blocks across and down get you there, with sashing and borders.

Units
Size the quilt for
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Added to both width and length. Dense quilting can take up 1–3″ or more.

Block setting
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Blocks to fit the target

Your quilt

  • 82″ × 102″finished quilt (208.3 × 259.1 cm)
  • 7 × 9blocks across × down
  • 63blocks to make
  • 84″ × 102″target for a queen mattress

Dashed outline: the top of the mattress, with the pillow tuck above it. Each square stands for one block.

  • Compared with the target: 2″ narrower, exactly on target.
  • Block area (inside the borders): 70″ × 90″.
  • Borders (finished, inside to outside): 2″, 4″, adding 12″ to each dimension.

Nearby layouts

Across × downBlocksFinished sizevs target (W / L)
7 × 9 shown6382″ × 102″−2″ / 0
8 × 97292″ × 102″+8″ / 0
6 × 95472″ × 102″−12″ / 0
7 × 85682″ × 92″−2″ / −10″
7 × 107082″ × 112″−2″ / +10″

Backing for this quiltBinding for this quilt

How the size is worked out

A bed quilt is the mattress plus the parts that hang over it. The drop is how far the quilt falls over each side and the foot: most quilters use 10–12″, and a deep or pillow-top mattress needs more. The pillow tuck is extra length at the head that tucks under and over the pillows; leave it at 0 if the quilt stops below them.

Width = mattress width + 2 × side drop.
Length = mattress length + foot drop + pillow tuck.

Measure your own mattress if you can: labels and countries differ, and the presets are only typical sizes. Quilting and washing shrink a quilt a little, so you can add a few inches for take-up.

Blocks, sashing and borders

The calculator takes the borders off the target, then fits whole blocks into what is left. Nearest picks the count closest to the target, At least never comes out smaller and At most never bigger. Sashing adds strips between blocks; with the outside option it also frames them. On point, each block takes up its diagonal, 1.414 times its side, and setting triangles fill the edges.

Worked example

A US queen mattress is 60 × 80″. With a 12″ drop and a 10″ pillow tuck the target is 84 × 102″. Borders of 2″ and 4″ take 12″ off each dimension, leaving 72 × 90″ for blocks: seven 10″ blocks across and nine down, 63 blocks, for a finished quilt of 82 × 102″.

Sources

  • Missouri Star Quilt Co., Quilt sizes chart: the width and length formulas, a 10–12″ drop and an 8–10″ pillow tuck, and the US mattress sizes used here.
  • Quilting Daily, Standard quilt sizes: a 10″ pillow tuck, and moderate to heavy quilting reducing the finished size by 1–3″ or more.
  • Wikipedia, Bed size: Twin XL, European and Australian mattress sizes, and the UK's imperial sizes (shown here in the metric sizes UK shops sell, such as 90 × 190 cm for a single).
  • C&T Publishing, Quilting tips: setting triangles: side setting triangles from squares of block × 1.414 + 1 1/4″ cut twice diagonally, corners from block ÷ 1.414 + 7/8″ cut once.

Quilt size questions

How big is a queen size quilt?

There is no single standard. A US queen mattress is 60 × 80″, so with a 12″ drop and a 10″ pillow tuck the quilt is about 84 × 102″. Quilting Daily suggests about 90 × 95″, which allows for a 15″ deep mattress and no pillow tuck. Measure the bed and choose the drop you like.

Should the drop cover the whole side of the mattress?

That is up to you. A drop equal to the mattress depth covers the side, a little more hides the edge of the base, and a coverlet or bedspread can reach further towards the floor. Measure the depth of your mattress, including any topper, and use that as the starting point.

What does on point mean?

The blocks are turned 45 degrees so they stand on a corner, forming diagonal rows. Each block then takes up its diagonal, about 1.414 times its side, and the gaps at the edges are filled with setting triangles. The calculator counts the whole blocks and the side and corner triangles you need.

Why is my quilt smaller than the target?

Blocks only come in whole numbers, so the layout usually lands a little above or below the target. Switch to At least to never come out smaller, change the border widths to make up the difference, or check the nearby layouts table for a closer fit.

Do border widths include seam allowances?

No. Every size here is finished: what shows on the quilt. When you cut border strips, add 1/2″ to the width for two 1/4″ seams, and cut them to the measured length of the quilt centre.