Get the exact curtain length, rod width, panel size, and fabric yardage for any window — no guessing, no short panels. Enter your window measurements below, and the calculator works out everything you need, with a visual diagram and a ready-to-shop list. It works for living rooms, bedrooms, kitchens, and bathrooms. It suits ready-made panels and fabric you sew yourself. You enter five simple measurements. The calculator does the math for you. It allows for rod height, rod extension, fullness, and hems. You see the rod width, the finished length, and the fabric yardage at once. The shopping list tells you what to buy, from the rod to the rings. No more panels that end too short or rods that stop too narrow. Measure once, buy once, and hang your curtains with confidence.
Visual diagram
Shopping list
How to measure
1. Measure the window width from one outside edge of the frame to the other, in inches. 2. Measure the window height from the top of the frame to the sill. 3. Measure from the floor up to where the rod will sit — this is the rod-to-floor height. 4. Decide how high above the window the rod will hang (4–12 inches) and how far it extends past each side (4–12 inches). 5. Choose an ending style — Sill, Apron, Floor, or Puddle — then enter everything in the calculator above.
Fullness guide
Fullness is how much fabric width you allow compared with the rod width. 1.5x looks flat and tailored, and works for sheer or casual panels. 2x is the standard choice for everyday curtains with soft, even folds. 2.5x looks luxurious and full, and suits heavier fabrics and formal rooms. If you are unsure, choose 2x.
Length styles explained
Sill length ends about half an inch above the sill, a neat look for kitchens and bathrooms. Apron length drops about 4 inches below the sill, covering the window apron. Floor length just kisses the floor (half an inch above it) and is the classic living-room and bedroom choice. Puddle length pools 2–6 inches of extra fabric on the floor for a relaxed, romantic look — best in low-traffic rooms.
Curtain tips
- Hang the rod high and wide to make the window look bigger.
- Use a metal tape measure and write each number down.
- Measure every window on its own, even if they look the same.
- Choose floor length for a classic look that suits most rooms.
- Steam or iron panels before you hang them for a neat finish.
- Fit the rod brackets into studs where you can, so the rod stays firm.
Common curtain mistakes
- Hanging the rod just above the frame, so the window looks short.
- Buying panels that are too narrow, with no fullness.
- Measuring the glass instead of the window frame.
- Choosing a rod that is too short for the window.
- Forgetting hem and header allowance when buying fabric.
FAQ
How high should I hang the curtain rod? Hang the rod 4–12 inches above the window frame — higher makes the window look taller. The calculator uses your rod-above measurement to work out the finished length. One panel or two? Two panels look balanced on most windows and close from the centre. One panel suits narrow windows and a simple, modern look. How much fullness do I need? Use 2x for standard folds, 1.5x for a flat tailored look, and 2.5x for luxurious fullness. What if my windows are different sizes? Measure each window separately and run the calculator for each one — do not average them, or panels will not fit. What rod length should I buy? Buy a rod at least as long as the rod width in your results. If you are between sizes, round up to the next size. A longer rod lets the open panels clear the glass. How wide should each panel be? The results show the per-panel finished width for your window. At 2x fullness on a 72 inch rod, each of two panels is 72 inches wide. What if my fabric has a pattern? Buy extra fabric so the pattern can match across both panels. Add one full pattern repeat to each cut length. Ask the shop to start each cut at the same point in the pattern.
Back to all free tools: Free Home Decor Tools & Calculators. Related reading: 10 Easy Ways to Make a Small Living Room Look Bigger and How to Create a Cozy Reading Nook in Any Corner of Your Home.
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