Curtain Size Calculator: How Wide and How Long?
Enter your window, rod height and the look you want. Get the rod width, number of panels, finished length and cut size, with a to-scale window drawing. Inches or millimetres. Runs in your browser.
When to use this
- You are buying ready-made curtain panels and need to know how many and how long.
- You are sewing curtains and want the rod width, fullness and cut size worked out.
- You want to compare floor, sill, apron and puddled lengths before you hang the rod.
How to use
- Choose inches or millimetres. Enter the window width, window height and sill height.
- Enter how far the rod extends past the window on each side and the rod height above the floor.
- Pick where the curtain should end, the heading style and the fullness.
- Enter the width of one panel, and tick the box if you will hang a pair.
- Press Calculate curtain size. Check the drawing and copy the sizes.
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Report a problem or suggest an improvement
Nothing is sent until you press Send. Your measurements are included only if you tick the box, and you can see the full report below first.
Examples
- 60 in window, rod at 84 in, floor length, rings, 2 times fullness, 50 in panels: The rod is 72 in wide, so you need 144 in of fabric: 3 panels, rounded up to a pair of 4. The finished length is 84 - 2 - 0.5 = 81.5 in.
- Sill-length curtains: Choose sill length and enter the sill height. The finished length is the rod height minus the sill height and the heading drop.
Understanding the result
The rod width is the window plus the extension on both sides. The fabric you need is the rod width times the fullness. Divide by the width of one panel and round up; a pair is rounded up to an even number. The finished length is the rod height minus where the curtain ends and minus the drop of the heading style. The cut size adds hem and header allowances.
Limitations
- This estimates sizes only. It does not check the rod or bracket strength, wall fixings, fire rating or blackout needs.
- Heading drops, hem and header allowances and the list of ready-made lengths are marked UNSOURCED. Check the product label or your fabric supplier.
- Fabric shrinkage, pattern repeat and lining are not modelled. Add extra fabric if you wash the curtains or match a pattern.
- Bay windows, sloped ceilings and floor-to-ceiling glass doors need a different measuring approach.
FAQ
How wide should curtains be?
A common rule is 1.5 to 2.5 times the width of the rod, so the curtains look gathered when closed. The tool multiplies the rod width by the fullness you choose and rounds up to whole panels.
How long should curtains be?
That depends on the look. Floor length just clears the floor, sill length ends at the window sill, apron length ends a little below it and puddled curtains rest on the floor. Pick one and the tool subtracts it from the rod height.
How far past the window should the rod go?
Many guides suggest about 4 to 8 inches on each side, so the open curtains do not cover the glass. The tool starts at 6 inches and you can change it.
How high should I hang the rod?
Higher than the window frame makes the ceiling look taller. Many people hang it halfway between the frame and the ceiling, but this is a style choice, so the tool only warns if the rod is below the top of the window.
Do I need an even number of panels?
Only if you hang a pair that opens in the middle. Tick the box to round up to an even number. A single panel on one side can be an odd count.
Does this tool store my measurements?
No. It runs in your browser. The share link keeps your numbers after the # sign, which is never sent to a server.
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