Fabric Calculator

How to calculate how much fabric you need

1. List every piece with its cut size – include seam allowances (usually 1.5 cm / ⅝ in for dressmaking, 1 cm / ⅜ in for crafts).
2. Check the usable fabric width – the width minus selvages, often 1–2 in less than the label.
3. Work out how many pieces fit side by side across the width.
4. Divide the number of pieces by that number to get rows, and multiply by the piece length.
5. Add allowance for shrinkage, pattern matching and straightening the cut edge, then round up.

Example: four cushion fronts at 18 × 18 in from 54 in fabric. Three fit across (3 × 18 = 54), so you need two rows: 2 × 18 = 36 in, or 1 yard. Add 5% for shrinkage (37.8 in) and round up – buy 1⅛ yards.

Common fabric widths

Allowances that change the answer

Pattern repeat

Prints that must line up – stripes, plaids, large florals – repeat at a set distance along the fabric. If the repeat is 24 in, each piece that must match takes up a whole number of repeats, so a 20 in piece effectively uses 24 in. Add at least one extra repeat to the total so you can choose where the pattern sits.

Shrinkage

Cotton, linen and rayon can shrink several percent in the first wash, so pre-wash before cutting and allow for it when you buy. Synthetics shrink very little. The calculator uses 5% by default for natural fibres; change it to 0% if your fabric is pre-shrunk.

Directional fabrics and nap

Velvet, corduroy, faux fur and one-way prints look different upside down, so all pieces must be cut in the same direction. That stops you rotating pieces to save fabric and usually adds 10–20% to the length.

Yards, metres and converting between them

1 yard = 0.9144 m and 1 m = 1.094 yd. Shops in the US usually cut in eighths of a yard; shops using metric often cut in 10 cm steps.

Project examples

• Throw pillow cover with envelope back (18 in insert): one 19 × 19 in front plus two 19 × 13 in back pieces – about ⅝ yd of 54 in fabric.
• Simple gathered skirt: two rectangles, each hip measurement + 10 in wide and finished length + 4 in long – for most sizes about 1½–2 yd of 45 in fabric.
• Quilt backing for a 60 × 80 in quilt: add 4 in each side (68 × 88 in); with 42 in usable width you need two lengths of 88 in seamed together – about 5 yd, or 2½ yd of 108 in wide backing.
• Binding for the same quilt: perimeter 280 in plus 10 in for joins; at 2½ in strips cut across 42 in width you need 7 strips – about ½ yd.

Tips to avoid buying too little

• Buy all the fabric for a project at once – dye lots vary between bolts.
• Add 10–15% if you are new to a pattern or the fabric is slippery.
• Check the pattern envelope's yardage chart and compare it with the calculator; the pattern includes pieces you might forget, such as facings and pockets.
• Keep scraps for testing stitches and pressing temperatures.

Worked example with a pattern repeat

You want six chair-seat covers, each cut 20 × 20 in, from a 54 in home-décor fabric with a 24 in vertical repeat, and every seat should show the same motif in the centre. Two pieces fit across the usable width (2 × 20 = 40 in; three would need 60 in). Six pieces therefore need three rows. Because each piece must start at the same point in the pattern, every row uses one full repeat of 24 in rather than 20 in, so the length is 3 × 24 = 72 in. Add one extra repeat (24 in) to position the motif where you want it: 96 in, or 2⅔ yards. Allow 5% for shrinkage if the fabric is washable and buy 2⅞ yards. Without matching, the same pieces would need only 60 in – the repeat adds more than half a yard.

Fabric cost and buying tips

Multiply the length you buy by the price per yard or metre. At $14 a yard, 2⅞ yards costs about $40.25. Remember that many shops cut only in set steps – eighths of a yard or 10 cm – and some charge for the full width even if you need a narrow strip, so the calculator rounds up to those steps before calculating cost. For expensive fabrics, draw your cutting layout to scale on squared paper first; rotating pieces or nesting small ones in leftover space can save a surprising amount.

Cutting on the bias

Pieces cut on the bias – at 45° to the selvage – stretch and drape more, which suits bias binding, slip skirts and cowl necks. Bias layouts waste more fabric because the pieces sit diagonally, so add roughly 25–50% to a straight-grain estimate, depending on the size of the pieces, or draw the layout to check.

Fabric for quilts

Quilters usually calculate each fabric separately: count the patches cut from it, work out how many patches fit across one strip of the usable width (often 40–42 in for quilting cotton), and multiply strips by strip width. A quilt top that needs 120 squares of 3½ in from one fabric gets 12 squares per 42 in strip, so it needs 10 strips – 10 × 3½ = 35 in, or about 1 yard (buy 1⅛ yards to allow for straightening the edge). Fat quarters (about 18 × 21 in) give 30 such squares each, so the same requirement could be met with four fat quarters.