What size curtains do I need?
Two numbers decide your curtains: width and length. For width, the panels together should be about 2 to 2.5 times the rod width so they look full and gathered rather than stretched flat — so you divide that total by the width of one panel to get how many panels to buy. For length, measure from the rod down to where you want the curtains to end (sill, just below the window, or the floor) and pick the nearest standard panel length. This calculator does both.
Tip: mount the rod about 4–6 inches above the window and extend it 8–12 inches past each side — measure the rod, not just the window, so curtains clear the glass when open. Curtains usually come in pairs.
Frequently Asked Questions
How wide should curtains be?
Combined panel width should be about 2× the rod width for a standard gathered look, or 2.5× for a fuller, more luxurious drape. Flat panels (1.5×) look sparse — most people prefer at least 2×.
How many curtain panels do I need?
Multiply the rod width by your chosen fullness, then divide by the width of one panel and round up. For most windows that’s 2 panels; wide windows and patio doors often need 3–4. Curtains are usually sold in pairs.
What length curtains should I buy?
Measure from the rod to where you want them to end. Standard lengths are 63, 84, 95, 108 and 120 inches. Floor-length looks best — pick the next size up from your measurement and hem if needed.
Should curtains touch the floor?
For a classic look, curtains should just kiss the floor. Add 2–3 inches for a soft “break”, or 6+ inches for a dramatic puddle. Avoid stopping above the floor — it makes windows look short.