Windows & Curtains
Curtain Length Calculator
Find the right curtain length for your window. Tell us where the rod sits and the look you want β from a crisp sill length to a dramatic floor puddle β and we return the exact panel drop to order.
Last updated: June 2026
Curtain length by hanging style
Curtain length is determined by three things: where the rod or track sits, the style of finish you want, and the window sill height. Getting it wrong by even 5 cm makes curtains look sloppy or awkward.
Formula used
Sill length: drop = sill height from floor
Below sill: drop = sill height + 4 cm (1.5")
Floor length: drop = rod height β 1 cm gap
Puddle: drop = rod height + 15 cm
Worked examples
Example 1 β Floor-length in a 2.5 m room: Rod at 240 cm β floor-length drop = 239 cm. Order panels at 242 cm to allow a 3 cm heading.
Example 2 β Sill length in a kitchen: Sill at 90 cm, rod at 130 cm β sill drop = 90 cm.
Example 3 β Dramatic puddle: Rod at 260 cm β puddle drop = 275 cm. Order 278 cm panels.
How to use this calculator
- Decide where your rod or track will go and measure its height from the floor.
- Measure the window sill height (for sill and below-sill styles).
- Select the style: sill, below sill, floor-length, or puddle.
- Add 2β3 cm for a top hem or heading tape when placing your order.
Curtain length reference table
| Style | Visual effect | Best for |
|---|---|---|
| Sill | Casual, airy | Kitchen, children's rooms |
| Below sill | Traditional | Cottage style, bay windows |
| Floor | Elegant, modern | Living rooms, bedrooms |
| Puddle | Romantic, dramatic | Formal dining, feature windows |
Notes & limitations
This calculator returns a finished panel drop. Always add hem and heading allowance. Related: Curtain Fabric Calculator.
Frequently Asked Questions
Should curtains touch the floor?
Floor-length curtains (with a 1β2 cm gap) are the most popular look in living rooms and bedrooms. They make ceilings appear higher. Sill-length curtains suit kitchens and children's rooms where floor-length panels are impractical.
How much extra fabric is needed for a floor puddle?
A puddle requires 15β30 cm (6β12 inches) of extra fabric pooling on the floor. Our calculator adds a standard 15 cm. For a dramatic romantic puddle, order 20β30 cm extra.
How high should I hang the curtain rod?
Hang the rod 15β20 cm above the window frame (or as high as the ceiling allows) to make windows appear larger. The calculator uses your actual rod height, so position the rod first, then measure.
What is the standard curtain panel drop in the UK and US?
Standard drops in the UK are 137 cm, 183 cm, 213 cm and 228 cm. In the US, common panel lengths are 63", 84", 96", 108" and 120". Custom lengths are always more precise.
How do I measure curtain length correctly?
Measure from the top of the curtain ring or eyelet (not the rod) to your desired finish point. Our calculator uses rod-to-floor height plus your chosen style to return the finished panel drop.