Cotton curtains are sized from the hardware, not the glass: measure the full pole or track width excluding finials, multiply by 2 to 3 for fullness, and measure the drop from the top of the pole to your chosen finish point.
One skipped step — measuring the window instead of the rod — is the reason a set of curtains arrives two feet too narrow, and the same mistake shows up on cotton panels where shrinkage can tighten the fit further. The steps below work for 100% cotton and any other fabric, because the hardware sets the size and the fabric only changes how you care for the finished panel.
What Do I Measure First, Width or Drop?
Width comes first, and it comes from the hardware — never the window glass. Measure the full width of the pole or track, stopping at the point where it meets the finials or decorative ends, because those ends don’t hold fabric and shouldn’t be counted.
That number is your base width, not your panel width. For eyelet, tab-top, and most pleated or gathered styles, fullness is calculated on the pole or track width, so you multiply the base to get the fabric you actually need. Home Depot’s measuring guide puts common fullness at 2x to 3x the rod or track width for a gathered look, and 1.5x to 2x for a flatter, more tailored hang.
Inside-mount measurements — the window opening or casing, plus a few inches of overlap — are useful for planning where the rod sits, not for ordering the finished panel width on its own. Order the dimensions width x length, with width listed first; that’s the order most retailers expect.
How Long Should Cotton Curtains Be?
Drop runs from the top of the pole or track down to wherever you want the fabric to stop — sill, just below the sill, or the floor. For eyelet and ring-top styles, start the tape at the top of the pole itself, since the rings and heading sit above it.
For made-to-measure pleated panels with a heading above the pole, add the heading allowance your product instructions specify, or the finished drop will sit short once the curtain hangs. Cotton behaves like any other fabric here, but the care label matters before you hem: cotton is a woven natural fiber and can shrink more than synthetics, so check the product’s washing instructions before cutting or locking in a final length.
Most guides suggest stopping slightly above the floor and slightly above radiators. Curtains that hang over a radiator trap heat behind the fabric instead of letting it circulate into the room, and floor-length panels that pool collect dust and wear faster along the hem.
If you want a specific look sorted before you measure, browsing tested 100% cotton curtain options makes it easier to pick a finish point and heading style first, then measure to match.
What Do Sizing Mistakes Cost You?
A narrow panel is the most common failure, and it shows up as a strip of light down the middle where two panels meet. Allowing extra width for overlap — so the panels cross slightly rather than just touching — closes that gap. Use a steel or metal tape measure, record in inches for US shopping, and round to the nearest 1/8 inch so your order and your hardware agree.
| Measurement Decision | What To Do | Common Mistake |
|---|---|---|
| Width base | Measure the pole or track, excluding finials | Measuring the window glass instead |
| Fullness | Multiply by 2x to 3x for a gathered hang | Ordering flat width with no multiplier |
| Drop start point | Top of the pole for eyelet and ring-top styles | Measuring from the rings or ceiling |
| Panel overlap | Add width so panels cross in the middle | Panels that just meet, leaving light gaps |
| Finish point | Sill, below-sill, or floor | Hanging over a radiator or pooling on the floor |
| Tools | Steel tape, inches, round to 1/8 inch | Soft tape or eyeballing the number |
The one fabric-specific check for 100% cotton happens before you commit to a hem length. Home-textile care labels flag shrinkage risk that synthetics don’t carry, and Dunelm’s measuring guide notes that made-to-measure headings sometimes need extra allowance above the pole — both change the final number you write down. Get the width, drop, and heading allowance confirmed, then order.
Ready to hang? Start with the pole width, multiply for fullness, lock the drop from the correct point, and add the overlap. Those four numbers cover every cotton panel on the market.
FAQs
Should I measure my window or my curtain rod?
Measure the curtain rod or track, not the window. The rod determines how wide the fabric hangs, and finials or decorative ends should be left out of the measurement. The window opening matters only for deciding where the rod sits, not for calculating panel width on its own.
How much extra width do cotton curtains need?
Cotton curtains need the same fullness as any other fabric: roughly 2x to 3x the rod or track width for a gathered look, and less for a flatter hang. Add a little extra beyond that so the two panels overlap slightly where they meet.
Will 100% cotton curtains shrink after washing?
Cotton is a woven natural fiber and can shrink more than synthetics, so check the care label before hemming or installing. Wash and dry according to the product’s instructions, and measure with that shrinkage in mind if the label flags it.
References & Sources
- The Home Depot. “How to Measure Curtains.” Supports rod-width measurement, fullness multipliers, and drop guidance.
- Dunelm. “Curtains Measuring Guide.” Supports heading allowance for made-to-measure panels above the pole.
- House Beautiful. “How to Measure Curtains.” Supports finish-point targets and measuring technique.
