Gutter & Downspout Calculator — m, cost
How to use this calculator
Enter the total gutter run (eave length), choose gutter size, specify the number of downspouts, corners, and section length. The calculator computes all materials: gutter sections, downspouts, hangers/brackets, elbows, end caps, and splash blocks.
Rule of thumb — 1 downspout per 10 m of gutter run. Brackets every 600 mm. Each downspout needs 2–3 elbows. Standard gutter sections are 3 m.
Saved Calculations
| Time | Run m | Sections | DS | Brackets | Elbows | Cost |
|---|
How to Calculate Gutter & Downspout Materials (Metric)
This calculator estimates all materials needed for a gutter installation per EN 12056-3: gutter sections, downspouts, brackets, elbows, end caps, inside/outside corners, and splash blocks. Enter the total eave length in metres, choose gutter size, and specify the number of downspouts.
Formulas
Gutter sections = total run / section length (3 m std), rounded up. Brackets = total run (mm) / spacing + 1. Elbows = downspouts × elbows per DS. Downspout sections = downspouts × ceiling(height / 3 m).
FAQ
How many downspouts? One per 10 m of gutter run. Add more for high-rainfall areas.
What size gutter? 125 mm handles most homes. Use 150 mm for large roof areas or heavy rainfall.
