Quilt Backing Calculator: Fabric Yardage and Size Chart

Work out backing fabric before you cut. Enter your quilt top size, overhang and fabric width, and see backing size, panels and yardage, with the formula in steps.

Calculate your backing

Quilt top width in

Quilt top length in

Overhang on each side in

Overhang is the extra backing beyond the quilt top on each side. Four inches on each side is a common starting point.

Fabric width

Seam allowance for pieced backing in

Seam allowance is used only when more than one panel is needed. It is the amount lost at each join between panels.

Fabric direction

Rotation swaps backing width and length and keeps the layout that needs less fabric. Do not rotate a directional print, because the print would run sideways on the back.

This calculator works out straight pieced backing only. For diagonal piecing, use the Diagonal Pieced Backing Calculator.

Your result

Enter your measurements, then calculate.

How the calculator works

Step 1: Backing size

Backing width equals top width plus 2 times overhang. Backing length equals top length plus 2 times overhang. Overhang is added on each side, so it is counted twice.

Step 2: Panels

If backing width fits in one fabric width, you need 1 panel. If not, each extra panel adds fabric width minus seam allowance, because seam allowance is lost at each join. Panels are rounded up, because a part panel still needs a full panel of fabric.

Step 2a: Compare both directions

The calculator tries the entered direction and the rotated direction, where backing width and length are swapped. It keeps the layout with the smaller total fabric length. On a tie, it keeps the entered direction. If you choose "Do not rotate" for a directional print, only the entered direction is used, and the other direction is not compared.

Step 3: Yardage

Total fabric length equals panels times backing length. Exact yardage equals total length divided by 36 in inch mode. Yardage to buy is exact yardage rounded up to the nearest 1/8 yard, so you buy enough, never short. In centimetre mode, total length is shown in centimetres, and metres to buy are rounded up to the nearest 0.1 metre. The unit toggle changes all inputs, outputs and rounding together.

Assumptions, shown next to the result

Fabric width is the nominal width, for example 44 inches. Seam allowance applies only at panel joins. Rotation is allowed by default, and it is turned off only when you choose "Do not rotate" for a directional print. No extra is added for shrinkage, cutting mistakes or longarm loading beyond the overhang you enter. If you need more room for longarm quilting, enter a larger overhang.

Backing and batting are different

Backing is the fabric layer on the back of the quilt. Batting is the soft middle layer between the quilt top and the backing. This calculator works out backing only. Use the Batting Calculator for batting.

Straight piecing and wide backing

Straight piecing joins panels along the length of the quilt. Wide backing at 108 inches or 120 inches often needs only one panel, with no seam, for most quilt sizes. If your quilt is wider than your fabric, even after one wide panel, you still need piecing. For a diagonal layout, use the separate Diagonal Pieced Backing Calculator, because diagonal geometry is different from straight piecing.

Yardage chart by quilt size

This chart uses the same formula as the calculator: 4 inches of overhang on each side, 44 inch fabric, 0.5 inch seam allowance, yardage rounded up to the nearest 1/8 yard. Where rotating the backing needs less fabric, the chart shows the rotated layout, because that is what the calculator chooses.

Quilt size	Top size	Backing size	Panels	Yardage to buy
Baby	36 by 48 in	44 by 56 in	1	1.63 yards
Lap	50 by 60 in	68 by 58 in	2	3.25 yards
Twin	68 by 88 in	76 by 96 in	2	5.38 yards
Full	80 by 92 in	100 by 88 in	3	7.38 yards
Queen	90 by 108 in	116 by 98 in	3	8.25 yards
King	108 by 108 in	116 by 116 in	3	9.75 yards

Chart yardage is a guide for the sizes shown. Your exact quilt size, overhang and fabric width may give a different result. Use the calculator above for your own measurements.

Worked example, checked against the calculator

Top size 60 by 72 inches, overhang 4 inches on each side, fabric width 44 inches, seam allowance 0.5 inch.

Backing width: 60 plus 2 times 4 equals 68 inches. Backing length: 72 plus 2 times 4 equals 80 inches.

Panels: 68 inches does not fit in 44 inches. Each extra panel adds 44 minus 0.5, which is 43.5 inches. Panels equal 1 plus the ceiling of (68 minus 44) divided by 43.5, which is 2 panels.

Total length in the entered direction: 2 times 80 equals 160 inches. Exact yardage: 160 divided by 36 equals 4.44 yards. Yardage to buy, rounded up to the nearest 1/8 yard, equals 4.50 yards. Rotated direction: backing 80 by 68 inches, still 2 panels, total length 2 times 68 equals 136 inches, yardage to buy 3.88 yards. The calculator compares both directions and chooses the rotated layout, because it needs less fabric.

With 108 inch wide backing, panels equal 1 in both directions. The entered direction needs 80 inches, 2.25 yards to buy. The rotated direction needs 68 inches, 2.00 yards to buy, so the calculator chooses the rotated layout.

Frequently asked questions

How do I calculate quilt backing?

Add overhang to both sides of your quilt top to get the backing size. Then work out how many fabric panels you need, multiply panels by backing length, and convert total length to yardage, rounded up to the nearest 1/8 yard.

How much backing fabric do I need?

It depends on quilt size, fabric width and overhang. Use the calculator above with your top size, overhang and fabric width. The result shows backing size, panels, total length and yardage to buy.

How many yards of backing do I need for a queen quilt?

For a 90 by 108 inch queen top, with 4 inches of overhang on each side and 44 inch fabric, you need 8.25 yards, rounded up to the nearest 1/8 yard, because the calculator rotates the backing to the cheaper layout. With 108 inch wide backing, you need 3.25 yards, where the entered direction is already cheaper.

What fabric width should I use for quilt backing?

Standard quilting cotton is 44 inches wide and usually needs piecing for larger quilts. Wide backing at 108 inches or 120 inches often needs only one panel, with no seam, for most quilt sizes.

Is quilt backing the same as batting?

No. Backing is the fabric layer on the back of the quilt. Batting is the soft middle layer between the quilt top and the backing. They are different layers, and they are calculated separately.

Do I need extra backing for longarm quilting?

Longarm quilting usually needs more overhang than hand quilting, because the quilt is loaded on rollers. If you are sending a quilt to a longarm quilter, check how much overhang they ask for, and enter that number in the overhang field.

Does the calculator rotate the backing?

Yes, by default it compares the entered direction and the rotated direction, and it chooses the layout that needs less fabric. The result shows both directions, so you can see the saving. If your backing fabric has a directional print, choose "Do not rotate" so the print runs the right way.

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