Free tool

Curtain length calculator

Enter your window and how you want the curtains to fall. You get the length, the stock size to buy, how long a rod and how wide the panels should be.

89.5 inches long

Measured from the rod, which hangs 90 inches above the floor.

  • Stock length to buy96 inches, hemmed 6.5 inches shorter
  • Rod length64 to 72 inches
  • Panels together, flat72 to 96 inches wide

See them at your window

Numbers say they fit. A picture says whether the color works with the room. Photograph it, add the curtains from any store, and see them in place.

Try it free How the furniture visualizer works

The rules behind the numbers

  • Rod height: at least 4 inches above the frame. With an 8 foot ceiling go nearly to the ceiling; in a taller room, about a foot above the window [1]. Nestig puts it at 3 to 6 inches above the frame [3].
  • Length: measure from the rod to the floor. Float ends half an inch to an inch above it, kiss just touches, a break adds 1 to 2 inches, and a puddle adds 3 to 6 [2]. The calculator uses half an inch for float.
  • Rod length: 8 to 12 inches past the frame on each side, so open curtains don't cover the glass [1].
  • Width: the panels together, flat, 1.5 to 2 times the window's width [3]. Bob Vila says at least twice [1].
  • Stock lengths: 63, 84, 96, 108 and 120 inches [1]. Buy the next one up and hem it.

Furnishing the same room? The rug size calculator and the coffee table size calculator size those too.

Sources

  1. Curtain lengths: a guide to sizing your window treatments, Bob Vila. Read October 30, 2026.
  2. How long should curtains be?, The Shade Store. Read October 30, 2026.
  3. Curtains 101: how to hang and style, Nestig. Read October 30, 2026.

Questions

How long should my curtains be?

Measure from the rod to the floor. For curtains that float, take off half an inch; to kiss the floor, use that length; for a break, add 1 to 2 inches; to puddle, add 3 to 6.

How high should I hang the curtain rod?

At least 4 inches above the window frame, and higher with a tall ceiling: near the ceiling in an 8 foot room, or about a foot above the window in a taller one.

How long should the curtain rod be?

8 to 12 inches past the frame on each side, so 16 to 24 inches wider than the window. Open curtains then rest on the wall and leave the glass clear.

How wide should curtains be?

The panels together, laid flat, should be 1.5 to 2 times the window's width. Two times looks full; 1.5 times looks tailored.

Are 84 or 96 inch curtains better?

Whichever is closest above the rod-to-floor length you need, then hem. In an 8 foot room with the rod high, 96 inches usually reaches the floor; 84 inches often ends short.

Will they look right in my room?

Length is half of it. To see the color and fabric, take a photo of the room and add the curtains from any store: Renderior shows them at your window, with a link to buy.

See the curtains at your window before you buy them.

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