Curtain Width Calculator
Enter the window width — and the rod width once you know it — and the fullness you want to find the total finished curtain width, including returns and a center overlap.
Curtain Width Calculator calculates in your browser.
Three widths that are easy to mix up
Curtain shopping involves three different widths. The window width is the glass and frame. The rod width is what the rod spans, usually a few inches past the window on each side. The finished curtain width is the flat width of all the fabric — wider than the rod, because curtains are gathered into folds to look full when closed.
This calculator multiplies the width covered — the rod if you enter one, otherwise the window — by the fullness you choose, then adds any fabric that wraps back to the wall at the ends (returns) or overlaps in the middle. The result is the total finished width to buy or make, split into two equal halves for a pair.
How to use the Curtain Width Calculator
- Choose inches or centimeters.
- Enter the window width, outside edge to outside edge of the frame.
- If you know the rod width, enter it — curtains must cover the rod, not just the window. Not sure yet? Work it out with the Curtain Rod Length Calculator.
- Pick a fullness: tap 1.5×, 2×, 2.5×, or 3×, or type your own.
- Choose a pair or one side, and add returns or a center overlap if your curtains have them.
How the calculation works
Width covered = rod width, or the window width when no rod is entered
Finished width = width covered × fullness + 2 × return + center overlap
For a pair, each side = finished width ÷ 2
A 64 in rod at 2× needs 128 in of curtain, 64 in each side. Add 3.5 in returns at both ends and a 3 in overlap and the total is 138 in; the extra 10 in isn’t gathered across the rod, so it doesn’t add fullness.
| Width covered | Fullness | Returns and overlap | Finished width | Per side |
|---|---|---|---|---|
| 48 in window, 64 in rod | 2× | None | 128 in | 64 in |
| 48 in window, 64 in rod | 2× | 3.5 in returns, 3 in overlap | 138 in | 69 in |
| 120 cm window, no rod | 2.5× | None | 300 cm | 150 cm |
| 36 in window, one side only | 1.5× | None | 54 in | 54 in |
Calculated on your device
- The width is worked out in your browser as you type; nothing is sent to a server.
- Your measurements and results are not sent to Looty Tools or stored.
- The calculator area, including the drawing, is masked from session-recording analytics.
Limitations
- Results are finished widths. Sewing from fabric needs extra for side hems, seams, and pattern matching, which depend on the fabric and heading.
- Fullness is a style choice; the presets are common starting points, not rules.
- Returns are entered as a depth at each end and the overlap as one total; corner and bay windows aren’t modeled.
- Curtain length isn’t calculated here.
- Widths up to 100 ft (30.48 m).
Related calculators
- Curtain Panel Count CalculatorEstimate how many curtain panels a window needs.
- Curtain Rod Length CalculatorEstimate how long a curtain rod should be.
- Length ConverterConvert inches, feet, meters, and other lengths.
Guides
- How Wide Curtains Should BeHow wide curtains need to be for your window or rod: the fullness formula, returns and overlap, and worked examples in inches and centimeters.
- Curtain FullnessWhat curtain fullness means, common fullness for each heading style, how much fabric each level takes, and why returns and overlap don’t add to it.
- Measuring a Window for CurtainsWhere to measure window width, how inside and outside mounts differ, how to measure the rod and returns, and what to write down before you shop.
- How Many Curtain PanelsWork out how many curtain panels to buy from the rod width, panel width, and fullness, why pairs round to even numbers, and when to buy one more.
- How Long a Curtain Rod Should BeFind curtain rod length from the window width and extension each side, with examples, a range to shop within, and where finials come in.
Curtain Width Calculator FAQ
- How wide should curtains be?
- Wider than the space they cover, so they gather into folds. For a 64 in rod at 2× fullness, you need 128 in of finished curtain width — 64 in on each side for a pair.
- What fullness should I use?
- About 1.5× suits flat or rod-pocket panels, 2× is common for most pleated curtains, and 2.5–3× gives sheers or formal drapes a fuller look. It is a style choice; the calculator accepts anything from 1× to 4×.
- Should I measure the window or the rod?
- The rod, once you know it. Curtains have to cover the rod’s full width, and most rods run past the window on each side. If you enter only the window width, the result covers the window alone — enough for a rod mounted inside the frame.
- What are returns and overlap?
- A return is the fabric that wraps from the front of the rod back to the wall at each end; overlap is extra width where the two halves meet in the middle. Neither is gathered across the rod, so they are added after the fullness: 128 in plus two 3.5 in returns plus a 3 in overlap is 138 in.
- Is finished width the same as fabric width?
- No. Finished width is the curtain’s flat width after hems and headings. Fabric off the bolt has to allow for side hems, seams, and pattern repeats, so a sewist needs more than the finished width.
- Are the measurements I enter sent anywhere?
- No. The check runs in your browser as you type. Your measurements and results are not sent to Looty Tools or stored, and the calculator area is masked from session-recording analytics. Refreshing the page clears it.
