Calculating your fabric needed is straightforward once you know the Curtain Fabric 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 Fabric Calculator.
What is Curtain Fabric?
The Curtain Fabric calculation tells you your fabric needed from a few simple inputs. The figure you are solving for here is the fabric needed.
The Curtain Fabric formula
This calculation combines several inputs through a multi-step method rather than a single one-line formula. Enter the values below and the calculator resolves each step in order. The inputs it needs are:
- Window/track width — a value measured in m. Example: 2 m.
- Fullness ratio — a number. Example: 2.
- Fabric roll width — a value measured in m. Example: 1.4 m.
- Finished drop (incl. hems) — a value measured in m. Example: 2.5 m.
How to calculate it step by step
- Write down the window/track width (for example, 2 m).
- Write down the fullness ratio (for example, 2).
- Write down the fabric roll width (for example, 1.4 m).
- Write down the finished drop (incl. hems) (for example, 2.5 m).
- Apply the formula above to get your fabric needed.
- Double-check the result with the Curtain Fabric Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Window/track width | 2 m |
| Fullness ratio | 2 |
| Fabric roll width | 1.4 m |
| Finished drop (incl. hems) | 2.5 m |
| Fabric needed | 7.50 |
| Fabric widths (drops) | 3 |
With window/track width of 2 m, fullness ratio of 2, fabric roll width of 1.4 m and finished drop (incl. hems) of 2.5 m, the fabric needed works out to 7.50.
Example 2
With window/track width of 4 m, fullness ratio of 2, fabric roll width of 1.4 m and finished drop (incl. hems) of 2.5 m, the fabric needed works out to 15.00.
| Result | Value |
|---|---|
| Fabric needed | 15.00 |
| Fabric widths (drops) | 6 |
Example 3
With window/track width of 1 m, fullness ratio of 2, fabric roll width of 1.4 m and finished drop (incl. hems) of 2.5 m, the fabric needed works out to 5.00.
| Result | Value |
|---|---|
| Fabric needed | 5.00 |
| Fabric widths (drops) | 2 |
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 Fabric Calculator does it instantly, for free, with the formula and a worked example built in.
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