How to use the quilt binding calculator
- Enter the finished width and length of your quilt.
- Enter the strip width you cut (2½ in / 6.5 cm is standard for double-fold binding).
- Check the usable fabric width — measure your fabric after trimming the selvages.
- Keep the extra for joining strips and turning corners (10–12 in / 25–30 cm).
Quilt binding formula
Binding length = 2 × (Width + Length) + Extra Strips = Binding length ÷ Usable fabric width → round up Fabric needed = Strips × Strip width Yards = Fabric needed (in) ÷ 36 → round up to ⅛ yd
Worked example
A 60 × 80 inch throw with 2½ inch binding strips and 40 inches of usable fabric width:
- Perimeter = 2 × (60 + 80) = 280 in; + 12 in extra = 292 in
- Strips = 292 ÷ 40 = 7.3 → 8 strips
- Fabric = 8 × 2.5 = 20 in = 0.56 yd → buy ⅝ yard
Binding for standard quilt sizes
| Quilt size | Typical size (in) | Strips (2½ in, 40 in usable) | Fabric to buy |
|---|---|---|---|
| Baby | 36 × 52 | 5 | ⅜ yd |
| Throw / lap | 60 × 80 | 8 | ⅝ yd |
| Twin | 66 × 90 | 9 | ⅝ yd |
| Full / double | 80 × 90 | 9 | ⅝ yd |
| Queen | 90 × 108 | 11 | ⅞ yd |
| King | 108 × 108 | 12 | ⅞ yd |
Values include 12 in extra. Quilt sizes vary between pattern makers, so always measure your own quilt.
Estimating bias binding
Bias binding is cut at 45° and stretches around curves. A quick way to estimate it is with a square of fabric: the side of the square you need is roughly the square root of (binding length × strip width). For 292 inches of 2½ inch binding: √(292 × 2.5) = √730 ≈ 27 inches, so start from a 27–28 inch square and cut continuous bias. Bias binding uses noticeably more fabric than straight-grain strips because of the angled cuts and seams, so buy an extra ¼ yard.
Binding tips
- Join strips with diagonal seams. They spread the bulk and are almost invisible. Each diagonal join uses roughly one strip-width of length, which the extra allowance covers.
- Press the strip in half lengthwise (wrong sides together) before sewing for double-fold binding.
- Start in the middle of a side, not at a corner, and leave a 6–8 inch tail to join the ends neatly.
- Mitre the corners by stopping ¼ in from the edge, folding up at 45° and back down.
- Buy a little extra if the fabric is directional or striped — matching the print uses more fabric.
- Pre-wash or not? If you pre-wash your quilt fabrics, pre-wash the binding fabric too so everything shrinks the same amount, and allow a few extra inches for shrinkage.
- Scrappy binding: leftover 2½ in strips from other projects work well — just make sure the total length is at least the binding length above.