Rail width, rail height and curtain drop using the hang high and wide rule.
How this works
Hang the rail high and wide: about two thirds of the way from the window top to the ceiling (or just under it), and 15 to 30 cm past the frame each side so open curtains stack off the glass. Floor length curtains stop 1 cm above the floor, sill length 1 cm above the sill and below sill 15 cm under it.
Questions people ask
How do I use the Curtain Size Calculator?
Fill in the fields, starting with “Window width (frame)”, “Window height (frame)” and “Window top from floor”, and change any other options that match your home. The answer, a drawing and practical tips update as you type, and the Copy link button saves your numbers in a link you can share.
Is the Curtain Size Calculator free?
Yes. The Curtain Size Calculator is free, with no sign-up, and works on phones, tablets and computers. The results are estimates to help you plan, so check with a qualified professional before structural, electrical, gas or plumbing work.