Gutter Length Table: Guttering needed (perimeter) by Roof length
Reference table of guttering needed (perimeter) for Gutter Length across a range of roof length values — exact, engine-computed figures you can read off at a glance.
Gutter Length Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Guttering needed (perimeter)
36.00
- Eaves only (two sides)
- 20.00
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Gutter Length Calculator
The Gutter Length Calculator works out your guttering needed (perimeter), along with 1 related figure in an instant. Enter roof length and roof width 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 roof length.
- Enter the roof width.
- Read off your guttering needed (perimeter), together with eaves only (two sides) — the calculator updates automatically, with no button to press.
Formula
The Gutter Length Calculator uses the formula:
Guttering needed (perimeter) = 2 × (Roof length + Roof width)
Worked example
For example, with roof length of 10 m and roof width of 8 m, the guttering needed (perimeter) is 36.00.
| Roof length | 10 m |
|---|---|
| Roof width | 8 m |
| Guttering needed (perimeter) | 36.00 |
|---|---|
| Eaves only (two sides) | 20.00 |
Results are estimates for educational use, not professional advice.
Frequently asked questions
For all sides, use the roof perimeter, 2 × (length + width). A 10 by 8 m roof needs 36 m.
Often only the eaves (two long sides) have gutters; the calculator shows both options.
Yes. Allow extra for corners, joins, downpipe outlets and cutting.
Roughly one per 50 m² of roof, more for heavy rainfall areas.
The Gutter Length Calculator uses the formula: Guttering needed (perimeter) = 2 × (Roof length + Roof width). For example, with roof length of 10 m and roof width of 8 m, the guttering needed (perimeter) is 36.00.
Enter the roof length. Enter the roof width. Read off your guttering needed (perimeter), together with eaves only (two sides) — the calculator updates automatically, with no button to press.
Related guides
How to Calculate Gutter Length: Formula, Steps & Examples
Learn how to calculate Gutter Length — the formula explained step by step, with worked examples and a free calculator to check your answer.