How Much Fabric Do I Need? Fabric Yardage Calculator
Enter your pattern pieces or the size of your pillow, table or window: the calculator lays the pieces out across the width of fabric, draws the cutting layout and gives the yardage to buy, rounded up to the next 1/8 yard.
Pattern pieces
Width and height of the rectangle around each piece, grainline running along the height. For a piece cut on the fold, enter the width shown on the pattern (half the full piece).
Seam allowance0.625 in
From your pattern (for example 5/8 in = 0.625 in).
Pattern repeat and shrinkageprinted fabric, washing
Given by the seller, in decimal inches (for example 10 1/4 in = 10.25 in). Leave empty for a solid fabric.
Ask the seller, or wash and measure a swatch. Leave empty if you prewash the fabric.
Yardage to buy
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- Length needed (before rounding)
- —
- Usable width
- 44 in (111.8 cm)
How the calculation works
Laying out the pieces: each piece is a rectangle (seam allowances included) placed across the fabric width, grainline along the length of the fabric. The tallest pieces go first, in rows; a piece goes into the first row where it fits across. The fabric length is the sum of the row heights. A piece cut on the fold takes twice its pattern width.
Yardage to buy: the length found, rounded up to the next 1/8 yard (4.5 in), and shown in yards with meters in parentheses.
Seam allowance: 5/8 in by default, the standard on most commercial patterns for woven fabrics (Threads), added on all four edges of each piece entered at its finished size (not along a fold). Change it to the one on your pattern, or say that the pieces already include it.
Piece wider than the fabric (large tablecloth, full curtain): it is cut from full fabric widths joined by lengthwise seams. Each join uses one seam allowance on each side.
Pattern repeat: each piece starts at the same point of the print, so its height is rounded up to the next multiple of the repeat: up to one full repeat may be added to each piece's length. Shrinkage: the usable width is reduced and the length increased by the percentage given by the seller.
Nondirectional fabric: for a pillow cover, a tablecloth or curtains, the calculator can turn the pieces a quarter turn if that saves fabric, and says so. It never does it when the turned piece would have to be joined, which would put a seam across it.
Pillow cover: front and back at the size of the pillow plus seam allowances; with an envelope closure, the back is cut in two overlapping parts (4 in overlap by default, a convention you can change), each with a double hem on the opening edge. Tablecloth: table size plus the drop on each side and a double hem all around; a round tablecloth is cut from a square.
Curtains: flat fabric width = rod length × fullness ratio, shared between the panels, plus a double hem on each side; length = finished length + bottom double hem + header (rod pocket) fabric. The calculator counts a 1/2 in double hem, so 1 in of fabric per edge, a convention for these projects. The fullness ratio and the header fabric have no default: they depend on the heading and the fabric.
Inches typed in are converted to centimeters for the calculation (1 in = 2.54 cm, 1 yd = 91.44 cm).
Sources:
- Sew4Home — "How To Measure Windows For Curtains + Drapes": fullness by fabric weight, hem and casing allowances
- Threads — "Industry Seam Allowances" (Laurel Hoffmann, 2018): 5/8 in, the standard on most commercial patterns for woven fabrics
Sources consulted November 10, 2026
Curtain fullness suggested by Sew4Home (flat fabric width ÷ width to cover)
| Fabric | Fullness ratio |
|---|---|
| Most curtains | 2 to 2.5 |
| Very sheer fabric | 3 or more |
| Heavy fabric | 1.5 |
Limitations
- Laying pieces out in rows is simple and predictable, but not optimal: nesting the pieces by hand on the fabric sometimes saves a few inches. The yardage chart on the pattern envelope, if it lists your size and fabric width, remains the reference.
- Each piece is reduced to the rectangle around it: curved or angled pieces actually use a little less, or more for pieces cut on the bias.
- Joined widths are counted as full fabric widths, without reusing the leftover of the last width for another piece.
- The 1/2 in double hem is shallow for curtains: Sew4Home suggests 2 to 4 in at the bottom and about 4 in at the top for hems and casings. Add the extra bottom hem to the finished length, and enter the top allowance as the header (rod pocket) fabric.
- Selvages (about 1/2 in each side) are not deducted. A 44/45 in cotton often has about 42 in usable. Choose a smaller width if needed.
Results are estimates. Always check your pattern's instructions and the product label or seller's information.
Frequently asked questions
How wide is fabric?
Fabric width (WOF) is measured selvage to selvage and printed on the bolt end or label. Yardage is cut along the length. Common widths: 44/45 in, 54 in, 58/60 in, 108 in (quilt backing).
Do I need to add seam allowances to my pattern?
Check the pattern instructions: most commercial patterns already include them, usually 5/8 in for woven fabrics and sometimes 1/4 in for knits (Threads). If the pieces are drafted without them, add the allowance around each piece, except along a fold.
Why buy more fabric for a print?
To keep the print continuous from one piece to the next, each piece must start at the same point of the design. In the worst case, the height of the repeat, given by the seller, is added to the length of each piece.
How full should curtains be?
Sew4Home suggests a fabric width of 2 to 2.5 times the width to cover for most curtains, 3 times or more for very sheer fabric and 1.5 times for heavy fabric. A pleated heading tape gives its own ratio in its instructions.