Quilt Fabric Calculator

Work out the squares, strips, binding and backing a quilt needs from its finished size and the size of one block.

A quilt is a grid of squares, which makes the arithmetic simple but unforgiving: a quarter inch lost at every seam adds up fast, and the backing and the binding are two more fabrics to buy. This calculator works out how many squares to cut, how much fabric the pieced top takes, and how much backing and binding to add.

At a glance

What you enter: Finished quilt width, Finished quilt length, Finished size of one square, Fabric width (bolt width), Waste allowance for the top, Binding strip width, Backing overhang per side, Backing
What you get: Fabric for the quilt top, Top fabric in metres, Backing fabric, Backing fabric in metres, Binding fabric, Finished width from whole squares, Binding strips to cut
Formula shown: Yes, every step, right below your results.
Cost and privacy: Free, no account needed, and nothing you type is stored.

See worked examples ↓ Read the FAQ ↓ Share this calculator ↓

Finished quilt width in

Finished quilt length in

Finished size of one square in

The size the square measures in the finished quilt, before the quarter inch seam is added back.

Fabric width (bolt width) in

Quilting cotton is almost always 44/45 in. Wide backing is 108 in.

Waste allowance for the top %

Covers the offcut at the end of each strip, squaring up, and the triangles left when squares are cut individually. 15 percent if every square is cut from continuous strips, 25 on a directional print.

Binding strip width in

2.5 in is the standard. 2.25 in is used on small quilts and tight curves.

Backing overhang per side in

Longarm quilters normally ask for 4 in on every side. 8 in gives more room for a big pattern.

Backing

Wide backing is 108 in and needs no seaming, which is why longarm quilters prefer it.

Reset

Results are estimates for general information only, always verify with a professional or official source before acting on them.

How to use the Quilt Fabric Calculator

1 Enter Finished quilt width (in)
2 Enter Finished quilt length (in)
3 Enter Finished size of one square (in), The size the square measures in the finished quilt, before the quarter inch seam is added back.
4 Enter Fabric width (bolt width) (in), Quilting cotton is almost always 44/45 in. Wide backing is 108 in.
5 Enter Waste allowance for the top (%), Covers the offcut at the end of each strip, squaring up, and the triangles left when squares are cut individually. 15 percent if every square is cut from continuous strips, 25 on a directional print.
6 Enter Binding strip width (in), 2.5 in is the standard. 2.25 in is used on small quilts and tight curves.
7 Enter Backing overhang per side (in), Longarm quilters normally ask for 4 in on every side. 8 in gives more room for a big pattern.
8 Enter Backing, Wide backing is 108 in and needs no seaming, which is why longarm quilters prefer it.
9 Press Calculate. You get Fabric for the quilt top, Top fabric in metres, Backing fabric, Backing fabric in metres, Binding fabric, Finished width from whole squares, Binding strips to cut, and every intermediate step stays visible under "How is this calculated?"
10 Change one number at a time to see what moves the result, that is usually the most useful thing a calculator can tell you.

Worked examples

Real numbers run through this calculator. Open any example to load it into the form above and change it.

Throw quilt in 5 inch squares

A 60 by 70 inch quilt in 5 inch finished squares, 44 inch fabric, a pieced backing.

You enter

Finished quilt width: 60 in
Finished quilt length: 70 in
Finished size of one square: 5 in
Fabric width (bolt width): 44 in
Waste allowance for the top: 20%
Binding strip width: 2.50 in
Backing overhang per side: 4 in
Backing: 1

You get

Fabric for the quilt top: 3.85 yd
Top fabric in metres: 3.52 m
Backing fabric: 4.33 yd
Backing fabric in metres: 3.96 m
Binding fabric: 0.49 yd
Finished width from whole squares: 60.00 in
Binding strips to cut: 7

Round the top fabric up to the next half yard, and check the dye lot on every piece.

Open this example in the calculator →

Baby quilt in 4 inch squares with wide backing

A 40 by 50 inch baby quilt in 4 inch finished squares, using 108 inch wide backing.

You enter

Finished quilt width: 40 in
Finished quilt length: 50 in
Finished size of one square: 4 in
Fabric width (bolt width): 44 in
Waste allowance for the top: 20%
Binding strip width: 2.25 in
Backing overhang per side: 4 in
Backing: 2

You get

Fabric for the quilt top: 1.99 yd
Top fabric in metres: 1.82 m
Backing fabric: 3.33 yd
Backing fabric in metres: 3.05 m
Binding fabric: 0.31 yd
Finished width from whole squares: 40.00 in
Binding strips to cut: 5

One length of wide backing covers it with no seam, which saves a lot of fiddling.

Open this example in the calculator →

Common Sewing Measurements Explained in Simple Terms

The waistband was two inches too small. I had the fabric cut, the interfacing fused, the pins already in, and when I wrapped it around my own waist to check, it stopped short with a gap you could fit...

How Much Fabric Do You Need for Your Sewing Project?

You can work out your fabric requirement in about 15-30 minutes with a tape measure, your pattern, and a bit of arithmetic. By the end of this guide you will know how to read a pattern envelope, measu...

How Much Seam Allowance Should You Use?

You have cut your fabric, pinned two pieces together, and then it hits you: how far from the edge do I actually sew? Get this wrong and your finished piece is either too tight to wear or too baggy to...

Frequently asked questions

How much fabric do I need for a queen size quilt?

A queen size quilt at 90 by 90 inches in 5 inch finished squares needs about 3 yards of 44 inch fabric for the top, which is 386 cut squares with cutting waste allowed. The backing takes two widths of 44 inch fabric joined, so roughly 4.5 yards, or 3 yards of 108 inch wide backing. Binding takes about three quarters of a yard. Buy the top fabric in one dye lot, because a queen quilt uses a lot of one colour and a lot mismatch shows.

What seam allowance do you use for quilting?

A quarter inch, and it is not a suggestion. A quilt with a hundred seams across it loses a quarter inch at each one, so a consistent quarter inch is what makes the blocks line up. A sixteenth of an inch too wide per seam adds up to more than six inches over the width of a queen quilt. Test your foot on scrap before you cut the good fabric.

How much bigger should the backing be than the quilt top?

Four inches on every side, so a 60 by 70 inch quilt needs a backing at least 68 by 78 inches. Longarm quilters clamp the backing to the frame and need that margin to load it; if the backing is tight the quilting pulls and the edge of the top can fall off the backing. Eight inches per side if the quilting is dense or the quilter asks for more.

How wide should binding strips be?

A 2.5 inch strip folded and sewn with a 3/8 inch seam gives a finished binding about half an inch wide on both sides, which is the standard for a bed quilt. Use 2.25 inches for a small quilt or a wall hanging, where a narrower binding looks better and the corners are easier to mitre. Cut on the cross grain rather than the straight grain, because a cross grain strip has a little give that lets it follow the edge.

How many squares do I need for a quilt?

Divide the quilt width by the finished square size and round up, then do the same for the length, and multiply. A 60 by 70 inch quilt in 5 inch squares is 12 squares across and 14 down, which is 168 squares. In 10 inch squares the same quilt is only 42 squares, but each one is four times the area, so the same amount of fabric.