Calculator + chartEnter your measurements below and it works the answer out.
Curtains are almost always bought too narrow. Enter your window and pick a look — this works out the rod width, panel width and drop.
| Look | Ratio | Total panel width for a 36 in window | Reads as |
|---|---|---|---|
| Flat | 1.0× | 36 in | Blinds, not curtains — avoid |
| Tailored | 1.5× | 54 in | Modern, minimal, shows the fabric pattern |
| Full | 2.0× | 72 in | The standard — soft folds when closed |
| Luxurious | 2.5× | 90 in | Deep folds, heavy drapes, formal rooms |
Total panel width is split across the panels you hang. Two panels on a 36 inch window at 2× fullness means each panel is 36 inches wide, not 18.
Rod width. The rod extends 4 to 10 inches past each side of the window so the curtains can stack off the glass when open. The calculator uses 6 inches per side, the middle of that range, and adds it to your window width.
Panel width. Fabric needed is the rod width multiplied by the fullness ratio. At 2× fullness a 48-inch rod needs 96 inches of curtain, split across the panels you hang. Buying panels that only match the window width is the commonest curtain mistake — they will not close, and they look thin even when open.
Drop length. Measured from the top of the rod, not the top of the window. Hanging the rod high — 4 to 6 inches above the frame, or halfway to the ceiling — makes the window and the room look taller, which is why the calculator assumes it.
Finished lengths are rounded to the nearest standard panel size (63, 84, 96, 108 or 120 inches), because those are what shops actually sell. If your calculated drop falls between two, size up and hem.
For a standard full look, about 72 inches of total panel width — usually two panels of 36 to 40 inches each. The rod itself should be around 48 inches so the curtains stack off the glass when open.
Four to six inches above the window frame, or higher if the ceiling allows — many designers go halfway between the frame and the ceiling. Hanging at the frame makes the window look squat; hanging high draws the eye up and makes the room read taller.
Floating half an inch above the floor is the easiest to live with — it looks intentional, and the curtains do not collect dust or catch when you open them. Breaking (an inch on the floor) is softer, and puddling (four inches) is formal but a nuisance to clean around.
Two for most windows, one on each side. Use four on a window wider than about 72 inches, or if you want the curtains to draw fully closed with proper folds. One panel only works on a narrow window you always leave open to one side.
US panels come in 63, 84, 96, 108 and 120 inches. 84 is the most common and suits a standard 8 ft ceiling with the rod hung above the frame. 96 or 108 suits 9 and 10 ft ceilings.