Calculating your curtain rod length is straightforward once you know the Curtain Rod Length formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Curtain Rod Length Calculator.
What is Curtain Rod Length?
The Curtain Rod Length calculation tells you your curtain rod length from a few simple inputs. The figure you are solving for here is the curtain rod length.
The Curtain Rod Length formula
The core formula is:
Curtain rod length = Window width + 2 × Extension each sideHere is what each input means:
- Window width — a value measured in cm. Example: 120 cm.
- Extension each side — a value measured in cm. Example: 15 cm.
How to calculate it step by step
- Write down the window width (for example, 120 cm).
- Write down the extension each side (for example, 15 cm).
- Apply the formula above to get your curtain rod length.
- Double-check the result with the Curtain Rod Length Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Window width | 120 cm |
| Extension each side | 15 cm |
| Curtain rod length | 150.0 |
With window width of 120 cm and extension each side of 15 cm, the curtain rod length works out to 150.0.
Example 2
With window width of 240 cm and extension each side of 15 cm, the curtain rod length works out to 270.0.
| Result | Value |
|---|---|
| Curtain rod length | 270.0 |
Example 3
With window width of 60 cm and extension each side of 15 cm, the curtain rod length works out to 90.0.
| Result | Value |
|---|---|
| Curtain rod length | 90.0 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Curtain Rod Length Calculator does it instantly, for free, with the formula and a worked example built in.
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