Fabric Calculator
Enter your project dimensions and fabric width to work out exactly how much fabric yardage to buy.
How to use the fabric calculator
- Choose your project type (curtains or upholstery) and unit system.
- Enter the finished width and drop (or cover dimensions) needed.
- Enter your fabric's roll width and pattern repeat, if any.
- Set the fullness ratio for curtains (2× is standard for a gathered look).
- Read the total fabric length needed, updated live.
How it works
For curtains: Total width needed = Track width × Fullness ratio. Widths of fabric = CEILING(Total width needed ÷ Fabric roll width). Cut drop length = Finished drop + hem and heading allowance, rounded up to the nearest pattern repeat. Total fabric = Widths of fabric × Cut drop length. For upholstery, the same repeat-rounding logic applies directly to each panel's cut length before summing all panels.
Examples
| Input | Result |
|---|---|
| 3 m track, 2× fullness, 137 cm fabric width, 2.4 m drop, 0 repeat, 25 cm allowance | ≈ 5 widths → 13.25 m |
| 10 ft track, 2× fullness, 54 in fabric width, 8 ft drop, 27 in repeat, 8 in allowance | ≈ 5 widths → 45 ft |
Frequently asked questions
What fullness ratio should I use for curtains?
2× to 2.5× fabric width relative to the track is standard for a gathered look; use 1.5× for a flatter, more minimal drape.
How much extra should I add for hems and headings?
Add roughly 20–30 cm (8–12 in) per drop to cover the bottom hem, header tape, and heading allowance — the calculator includes a default allowance you can adjust.
How does pattern repeat affect fabric needed for upholstery?
Each cut panel must be rounded up to the nearest full repeat so the pattern lines up across seams, which typically adds 10–20% extra yardage versus plain fabric.
Can I use this calculator for roman blinds or cushions?
Yes — treat each blind or cushion cover as one panel and enter its finished width and drop; skip the fullness ratio (set it to 1×) since blinds and cushions aren't gathered.
Should I buy extra fabric beyond the calculated amount?
A small buffer of 10% is wise for cutting errors, especially with large pattern repeats or slippery fabrics that are harder to cut precisely.