Curtain size calculator
Enter the window width and height, choose the fullness and length style, and see how many panels you need and how long.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter window width, window height, rod extension on each side, rod height above window, fullness and width of one panel.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Rod = window width + 2 × side extension. Fabric width = rod × fullness. Panels = fabric width ÷ panel width, rounded up. Drop = rod height above window + window height + chosen extra drop.
Example
Inputs: Window width = 150 cm, Window height = 150 cm, Rod extension on each side = 15 cm, Rod height above window = 15 cm, Fullness = 2 × (standard). Result: Panels needed: 3; Panels rounded up to pairs: 4; Rod length: 180 cm.
Limits and caveats
- Fullness ratios and drops are common tailoring conventions, not a binding standard.
- Hem allowances are not included. Use the curtain fabric calculator for meters of fabric.
Questions about this tool
What does 2 × fullness mean?
The flat fabric is twice as wide as the rod, so it forms clear folds when closed. Sheer curtains usually need more fullness.
Why extend the rod past the window?
So the open curtains stack on the wall instead of covering the glass, and the window looks wider.
Why stop 1 cm above the floor?
It keeps the fabric from dragging and getting dirty while still looking full length.