Curtain size calculator
Window width in, panel sizes out — the fullness, rod, and drop conventions from our sizing guide, done for you.
Measure the window's width across the frame, then decide where the rod will go — 4 to 6 inches above the frame, or higher — and measure from that spot straight down to the floor. Those two numbers are all this needs.
The reasoning behind every number here is in the full curtain sizing guide — including the sill and apron landings this calculator doesn't cover, and why measuring from the frame instead of the rod is the classic mistake.