Quilt Border Yardage Calculator

Enter the size of your quilt top and the finished width of the border to find how many strips to cut, how long each border piece must be and how many yards of fabric to buy, for butted or mitered corners.

How to use the quilt border calculator

Measure your finished quilt top before adding any border: measure the width and length through the centre, not along the edges, because edges stretch during piecing. Enter the finished width you want the border to be, choose butted or mitered corners, and choose whether you will cut strips across the width of the fabric and join them, or along the length for seamless borders.

The calculator adds seam allowances, works out each border's cut length and converts the total into strips and yards. Yardage is rounded up to the nearest eighth of a yard, the smallest cut most quilt shops sell.

The border maths explained

For a butted border, the side borders are sewn first and are cut to the length of the quilt top. The top and bottom borders are then added across the full width, including the two side borders, so they are cut to the quilt width plus twice the finished border width.

For a mitered border, all four strips extend past the corners so they can be sewn at 45°. Each strip is cut to the side it is sewn to plus twice the finished border width, plus a few inches of margin; the calculator adds 4 inches.

1. Cut strip width = finished border width + 2 × seam allowance (¼" each side, so +½").
2. Total border length = 2 × side length + 2 × top/bottom length.
3. Strips across the fabric = total length ÷ usable fabric width, rounded up.
4. Fabric length = number of strips × cut strip width.
5. Yards = fabric length in inches ÷ 36.

Worked example

A quilt top measures 60 × 72 inches and you want a 4-inch finished butted border. Strips are cut 4½ inches wide. The two side borders are 72½ inches long and the top and bottom borders are 60 + 8 + ½ = 68½ inches, for a total of 282 inches. With 40 inches of usable width per strip, you need 282 ÷ 40 = 7.05, so 8 strips. Eight strips × 4½ inches = 36 inches of fabric: exactly 1 yard, so buy 1⅛ yards to allow for straightening the fabric edge.

Usable fabric width

Quilting cotton is usually sold as 42–44 inches wide, but after removing selvages and squaring the edge you can rely on about 40–42 inches. Wide-back fabrics are 108 inches wide. If you pre-wash your fabric it may shrink a little, so measure after washing. Entering a slightly smaller usable width is the safest way to avoid running one strip short.

Pieced or lengthwise borders?

Joining strips with a diagonal (45°) seam spreads the bulk and makes the join less visible, but uses slightly more length per seam — roughly the strip width. The calculator's estimate includes no extra for diagonal joins; add one strip if you plan to use them on a wide border.

Measuring and attaching borders so they lie flat

• Measure the quilt through the centre in both directions and cut borders to that measurement, not to the edge length.
• Fold the border and the quilt edge in half and quarters and pin at the marks so any fullness is eased in evenly.
• Sew with the border on the bottom if the quilt top is fuller, so the feed dogs help ease it.
• Press seams toward the border.
• Measure again before cutting the second pair of borders; the first pair changes the width.

Choosing a border width that suits the quilt

Border width is a design decision as much as a fabric one. A common guideline is to keep a single border narrower than the largest block in the quilt, so the centre stays the focus; for 12-inch blocks, borders of 3 to 6 inches usually look balanced. A narrow inner border of 1 to 1½ inches in a contrasting colour can act like a picture mat before a wider outer border. For a bed quilt, work backwards from the mattress: add the drop you want on each side, subtract the size of the pieced centre, and split the difference across your borders. Wider borders also give more room for quilting motifs, but they stretch more easily, so pin carefully and consider cutting them along the lengthwise grain.

Multiple borders and binding

For a second border, run the calculator again using the new quilt size including the first border. Binding is calculated separately: add the perimeter of the finished quilt plus about 10–12 inches, then divide by usable fabric width to get the number of binding strips (usually 2¼ or 2½ inches wide).