Curtain Rod Length Table: Curtain rod length by Window width
Reference table of curtain rod length for Curtain Rod Length across a range of window width values — exact, engine-computed figures you can read off at a glance.
Curtain Rod Length Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Curtain rod length
150.0
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Curtain Rod Length Calculator
The Curtain Rod Length Calculator works out your curtain rod length in an instant. Enter window width and extension each side and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the window width.
- Enter the extension each side.
- Read off your curtain rod length — the calculator updates automatically, with no button to press.
Formula
The Curtain Rod Length Calculator uses the formula:
Curtain rod length = Window width + 2 × Extension each side
Worked example
For example, with window width of 120 cm and extension each side of 15 cm, the curtain rod length is 150.0.
| Window width | 120 cm |
|---|---|
| Extension each side | 15 cm |
| Curtain rod length | 150.0 |
|---|
Results are estimates for educational use, not professional advice.
Frequently asked questions
Add an extension on each side to the window width. A 120 cm window with 15 cm each side needs a 150 cm rod.
Extra width lets curtains clear the glass when open, making the window look larger and letting in more light.
About 15 to 25 cm each side is common, more for heavier or layered curtains.
Yes. Mounting higher than the window adds a sense of height, though it does not change the rod length.
The Curtain Rod Length Calculator uses the formula: Curtain rod length = Window width + 2 × Extension each side. For example, with window width of 120 cm and extension each side of 15 cm, the curtain rod length is 150.0.
Enter the window width. Enter the extension each side. Read off your curtain rod length — the calculator updates automatically, with no button to press.
Related guides
How to Calculate Curtain Rod Length: Formula, Steps & Examples
Learn how to calculate Curtain Rod Length — the formula explained step by step, with worked examples and a free calculator to check your answer.