Curtain size calculator

Curtains hung wrong make windows look smaller and ceilings lower. Enter the window and this gives you the rail position, the drop, and how much fabric you actually need.

The window
How they should hang

1.60 m × 2.39 m

Rail 1.60 m wide, mounted at 2.40 m from the floor. Curtain drop 2.39 m.

Rail height from floorNear the ceiling — makes the window read as taller
2.40 m
Rail widthExtending 20 cm each side
1.60 m
Curtain dropMeasure from the rail, not the frame
2.39 m
Fabric per panelTwo panels at 2× fullness
1.60 m
Total fabric width
3.20 m
Stack-back each sideWhere the curtain sits when open
20 cm

The rail width matters as much as the height. Extending 20 cm each side means the curtains stack against the wall when open rather than over the glass — which both admits more light and makes the window appear wider.

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