How to Measure for Curtains

Hang high and wide

Two decisions do almost all the visual work, and both happen before you buy the curtain: how high the rod goes, and how far past the window it extends.

Mounting the rod 4 to 8 inches above the frame draws the eye up and makes the window read taller than it is. In a room with high ceilings, mounting just below the ceiling line is even stronger. Extending the rod 6 to 12 inches past each side lets the curtains sit off the glass when open, which means more daylight and a window that looks wider.

Width: the two-times rule

A curtain panel that is exactly as wide as the window will hang flat and look like a bedsheet. Fullness comes from having more fabric than the opening needs.

Total finished curtain width should be roughly twice the width of the area the rod covers. Two panels each 50 inches wide across a 50 inch window gives you 100 inches of fabric for 50 inches of opening, which is right. For sheer or lightweight fabric, push to 2.5 times, since thin fabric needs more gathers to look deliberate.

Length: pick your relationship with the floor

Measure from the top of the rod to the floor, then choose one of three finishes.

• Kissing the floor: the hem just touches. The cleanest, most tailored option, and the hardest to get right if your floor is uneven.
• Slight break, 1 to 3 inches of extra length: forgiving, softer, and the most practical choice for most rooms.
• Puddled, 6 or more inches extra: dramatic and traditional, but it collects dust and gets in the way of anything that moves, including a vacuum.

Standard lengths and what they suit

Curtains are sold in fixed drops: 63, 84, 96, 108, and 120 inches. With a rod at standard height, 84 inches suits an 8 foot ceiling, 96 suits 9 feet, and 108 suits 10 feet. If you are hanging near the ceiling, size up one step from what the window alone would suggest.

Do not buy short and hope. A curtain that stops above the floor makes the ceiling look lower, which is the exact opposite of what curtains are for.

Blackout, thermal, and sheer

Blackout lining is the difference between a bedroom that works for a shift worker and one that does not. It also adds noticeable weight, so check the rod is rated for it and use more brackets than you think.

Thermal lining is worth it on a single-glazed or north-facing window, where it measurably cuts draughts. Sheers are for privacy without darkness, and are often layered on a double rod behind heavier panels rather than used alone.