By Team Quiltdom
Use this free quilt border calculator to find out how much fabric to buy for your quilt borders and exactly how to cut them. Enter the size of your quilt top and the width of each border, and it tells you how many strips to cut, the length of each side strip, the yardage for each border, and your finished quilt size.
It handles up to three borders, butted or mitered corners, and diagonal or straight seams for joining strips.
Quilt Border Calculator
All measurements in inchesNext step: work out the backing and batting for this quilt, then see our guide to binding a quilt.
Cut strip widths include 1/4 inch seam allowances on both edges. Strips are cut across the fabric width and sewn end to end into one long strip, then cut to length. A diagonal join uses about one strip width of length, a straight join 1/2 inch. Each border includes 1 extra inch for straightening the fabric edge, then rounds up to the nearest 1/8 yard. Mitered strips include 3 extra inches for trimming the corners.
How To Use The Quilt Border Calculator
- Measure your quilt top through the center. Measure side to side across the middle for the width and top to bottom for the length. The edges stretch as you sew, so the center measurement is the true size, and it keeps your borders from rippling.
- Enter the finished width of each border. Start with the innermost border. Leave Border 2 and Border 3 at 0 if you only want one. The calculator adds the 1/2 inch seam allowance for you.
- Choose your corners and seams. Butted corners are the easiest. Diagonal seams hide better when you join strips; straight seams use a little less fabric.
- Read your cutting list. You get the yardage for each border, how many strips to cut, and the exact length of each side strip.
How To Calculate Quilt Borders By Hand
Here is the math behind the calculator, using a quilt top that measures 60 1/2 x 72 1/2 inches through the center and one 4 inch border with butted corners.
- Find the cut width. Add 1/2 inch to the finished width for seam allowances. A 4 inch border is cut 4 1/2 inches wide.
- Find the side strip length. Side borders go on first, so they are as long as the quilt top: 72 1/2 inches each.
- Find the top and bottom strip length. These cover the side borders too, so add twice the finished border width to the quilt width: 60 1/2 + 8 = 68 1/2 inches each.
- Count the strips. You need 2 x 72 1/2 + 2 x 68 1/2 = 282 inches of border. Each 42 inch strip gives you about 37 1/2 inches after a diagonal join, so 8 strips cover it.
- Convert to yards. Eight strips at 4 1/2 inches is 36 inches, plus 1 inch to straighten the fabric edge. That's 37 inches, so buy 1 1/8 yards.
The formula: strips = total border length ÷ (usable fabric width minus one strip width per diagonal join), rounded up. Yardage = (strips x cut width + 1 inch) ÷ 36, rounded up to the next 1/8 yard.
For mitered corners, every strip is cut longer: the side of the quilt top plus twice the finished border width, plus about 3 inches for trimming the corner.
How Much Fabric For A Quilt Border? (Chart)
This chart shows the yardage for one border with butted corners and diagonal seams, cut from 42 inch quilting cotton. The quilt top sizes are measured through the center. Use the calculator above for your exact numbers.
| Quilt top | 2 in border | 4 in border | 6 in border |
|---|---|---|---|
| Baby, 36 1/2 x 48 1/2 in | 3/8 yd | 3/4 yd | 1 1/8 yd |
| Throw, 48 1/2 x 60 1/2 in | 1/2 yd | 1 yd | 1 3/8 yd |
| Twin, 60 1/2 x 84 1/2 in | 5/8 yd | 1 1/4 yd | 1 3/4 yd |
| Queen, 84 1/2 x 96 1/2 in | 3/4 yd | 1 3/8 yd | 2 1/8 yd |
| King, 96 1/2 x 96 1/2 in | 3/4 yd | 1 1/2 yd | 2 1/4 yd |
Butted Or Mitered Corners?
Butted corners are the quickest. You sew the side borders on, press, then sew the top and bottom borders across the ends. They suit most quilts and all beginners.
Mitered corners meet at a 45 degree angle, like a picture frame. They take more fabric and more care, but they look polished on striped or directional fabric and on wide outer borders, where a stripe would otherwise stop abruptly at the corner.
Cutting Borders Across Or Along The Fabric
Most quilters cut border strips across the width of the fabric and join them. It uses the least yardage. Cutting along the length of the fabric means no joins at all, which looks cleaner on a wide border or a large print, but you need enough yardage to match your longest side. The calculator shows both numbers so you can decide.
Quilt Border Calculator FAQ
How much fabric do I need for a quilt border?
For a throw quilt top measuring 48 1/2 x 60 1/2 inches, a 4 inch border with butted corners needs about 1 yard of 42 inch quilting cotton. Wider borders, bigger quilts and mitered corners all need more, so enter your own sizes in the calculator above.
How do you measure a quilt for borders?
Measure through the center of the quilt top, not along the edges. The edges stretch as you piece, and cutting borders to the center measurement keeps the quilt square and the borders flat. Cut your side borders to the center length, sew them on, then measure the width through the center again for the top and bottom.
How wide should a quilt border be?
Most quilts use 1 to 2 inches for a thin inner border and 4 to 8 inches for an outer border. Lay your fabric next to the quilt top before you cut to see what looks balanced.
Should I join border strips with diagonal or straight seams?
Diagonal seams spread the bulk and are harder to spot, so they are the usual choice. Straight seams use a little less fabric and are fine on busy prints.
Do I add the binding to the border fabric?
No. Binding is cut separately, usually 2 1/4 to 2 1/2 inches wide. Our beginner's guide to binding a quilt walks you through it.
Plan The Whole Quilt
Start with the quilt size calculator to work out how many blocks you need, the quilt sashing calculator if you are putting strips between your blocks, use this quilt border calculator for the borders, then finish with the quilt backing calculator. All of our tools are on the quilting calculators page.