You've found the perfect pattern. You're standing in front of a bolt of fabric you love. And then the question hits: how much do I actually buy? Buy too little and you're back at the store hoping they still have it. Buy too much and your stash grows another unfinished layer.
The good news: quilt yardage math is more predictable than it looks. Once you understand the formula, you can calculate any project in your head — or better, let your phone do it for you.
The three numbers you always need
Every yardage calculation comes down to three things:
- Cut size — the size of your piece before sewing (includes seam allowance)
- Quantity — how many pieces you need of that fabric
- Usable width of fabric (WOF) — almost always 40–44 inches after washing and selvage removal. Use 40 inches to be safe.
Block yardage: the core formula
For any pieced block, calculate yardage fabric-by-fabric. For each fabric in a block:
Step 1 — Total pieces needed
pieces per block × number of blocks = total pieces
Example: 4 pieces/block × 24 blocks = 96 pieces
Step 2 — Pieces per strip
⌊ 40 ÷ cut width ⌋ = pieces per strip
Example: ⌊ 40 ÷ 4.5 ⌋ = 8 pieces per strip
Step 3 — Strips needed
⌈ total pieces ÷ pieces per strip ⌉ = strips needed
Example: ⌈ 96 ÷ 8 ⌉ = 12 strips
Step 4 — Yardage
(strips × cut height) ÷ 36 × 1.10 = yards
Example: (12 × 4.5) ÷ 36 × 1.10 = 1.65 yards → buy 1¾ yards
⌊ ⌋ means floor (round down) · ⌈ ⌉ means ceiling (round up)
Binding yardage
Binding is often an afterthought, but it's easy to calculate. Most quilters cut binding strips at 2½ inches wide (for a double-fold binding).
Binding calculation
(quilt perimeter + 10″ overlap) ÷ 40 = strips needed
Example: (2 × 60 + 2 × 70) + 10 = 270 inches ÷ 40 = 7 strips (round up to 7)
Yards of binding fabric
strips × cut width ÷ 36 × 1.10 = yards
Example: 7 × 2.5 ÷ 36 × 1.10 = 0.54 yards → buy ⅝ yard
Backing yardage
Quilt backing needs to be 4–6 inches larger than your quilt top on all sides (so your longarm quilter has room to work). For most quilts, add 8 inches to both the width and height.
The tricky part is that standard quilting cotton is 40–44 inches wide, but most quilts are wider than that. You'll need to piece the backing with a seam.
Quilts up to 36" wide (no seam needed):
Backing — narrow quilts
(quilt height + 8″) ÷ 36 = yards
Example: (60 + 8) ÷ 36 = 1.89 yards → buy 2 yards
Quilts 37–80" wide (one horizontal seam):
Backing — standard quilts
2 × (quilt height + 8″) ÷ 36 = yards
Example: 2 × (60 + 8) ÷ 36 = 3.78 yards → buy 4 yards
Quilts wider than 80":
You'll need three widths of fabric. Calculate as 3 × (quilt height + 8″) ÷ 36, or consider using 108" wide backing fabric to eliminate seams entirely.
Common yardage mistakes (and how to avoid them)
❌ Forgetting seam allowance
✓ Your cut size is always larger than your finished size. A 4" finished square requires a 4.5" cut square (¼" seam on each side).
❌ Using 44" as usable width
✓ After washing and removing selvages, you realistically get 40–42". Use 40" for safe calculations.
❌ Not accounting for directional prints
✓ One-way prints can only be cut in one direction, which sometimes halves your yield. Add 20–25% extra for directional fabrics.
❌ Calculating the whole quilt as one fabric
✓ Each fabric in a block needs its own calculation. A 9-patch block uses three different fabrics — calculate each separately.
❌ Skipping the waste buffer
✓ Fabric gets distorted, cut crooked, or used as a test strip. Always add at least 10%. It's cheaper than a second trip to the store.
Quick reference: common quilt sizes
These are finished quilt top dimensions. Add 8" for backing, calculate binding from perimeter.
| Size | Dimensions | Typical backing |
|---|---|---|
| Baby / Crib | 36″ × 54″ | 2¼ yards |
| Lap / Throw | 54″ × 72″ | 4 yards |
| Twin | 60″ × 80″ | 5 yards |
| Full / Double | 72″ × 90″ | 5½ yards |
| Queen | 90″ × 108″ | 8 yards |
| King | 108″ × 108″ | 9½ yards |
Stop doing this math by hand
Honestly, calculating yardage manually is one of those things that sounds simple but eats up 20 minutes every time you start a new project. Miss one step and you're either short on fabric or you bought 3 yards too many.
StitchLogic does all of this automatically. Enter your quilt size, choose your pattern, and the app calculates exact yardage for every fabric in the project — blocks, binding, and backing — in seconds. It also lets you preview your fabrics in the actual quilt before you buy anything.
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Try the Yardage Calculator in StitchLogic
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