Curtain fabric calculator
Curtains are wider than the window so they fall in folds. The fullness factor sets how much wider; the fabric width sets how many drops you sew together.
Your measurements
Result
- Curtain width needed
- 3.00 m
- Fabric widths (drops)
- 3 pcs
- Fabric needed
- 7.20 m
Assumes vertical drops sewn side by side; patterned fabrics need extra for matching. Add 15–20 cm for hems and heading.
How the calculation works
- Curtain width = window (or track) width × fullness (1.5, 2 or 2.5).
- Fabric widths = curtain width ÷ fabric width, rounded up.
- Fabric needed (m) = fabric widths × curtain height.
Worked example
For a 1.5 m window and fullness 2 the curtain is 3 m wide. From 1.4 m wide fabric you get 3 widths, and at a 2.4 m drop you need 3 × 2.4 = 7.2 m.
What the calculator assumes
- Fullness 2 gives rich, classic folds; 1.5 suits heavy fabrics or a straighter look; 2.5 sheer voiles.
- Drops are sewn vertically, side by side.
When to adjust the result
- Add 15–20 cm to the height for the hem and the heading.
- Wide fabrics of 2.8–3 m (voiles) are usually used railroaded: you buy a length equal to the curtain width and the height comes from the fabric width.
- Patterned fabrics must be matched — allow one pattern repeat extra per width.
Making curtains look full and fit well
Fullness is what makes curtains look generous: fabric width of 1.5–2.5 times the track width depending on the heading tape. Extend the pole or track 15–25 cm beyond the window on each side so open curtains do not block the glass.
Hang the pole well above the window — 10–15 cm or more — to make the room look taller. Floor-length curtains should just touch the floor or stop 1 cm above it. Wash or check shrinkage before hemming natural fabrics, and allow for pattern repeats when joining widths.
Frequently asked questions
How wide should curtains be?
Usually 1.5–2.5 times the track width, depending on the fabric and the look you want.
How much extra for hems?
About 15–20 cm on the drop for the bottom hem and the heading.
How wide should curtains be?
Track width × the fullness of the heading (often 2×) plus allowances for side hems and overlaps, divided between the two curtains.
How long should curtains be?
From the pole or track to the floor, minus about 1 cm, unless you want them to puddle or sit on the windowsill.