Gutter Length, Sections and Downspout Calculator
Calculate gutter length with allowance, whole stock sections and a planning count of downspouts.
Formula
L = Eave length × Number of gutter runs × (1+Waste allowance/100); N = ceil(L/Piece length)
Planning estimate. Check product specifications and local requirements before purchasing.
Worked example: Gutter Calculator
Measurements in this example
| Eave length | 10 m |
|---|---|
| Number of gutter runs | 2 |
| Piece length | 3 m |
| Maximum run per downspout | 12 m |
| Waste allowance | 5 % |
Calculated quantities
| Total length | 21 m |
|---|---|
| Whole pieces | 7 |
| Downspouts | 2 |
What to check
This calculation uses: Eave length, Number of gutter runs, Piece length, Maximum run per downspout, Waste allowance. It returns: Total length, Whole pieces, Downspouts.
Use the units beside each field. The values in the worked example are starting inputs; replace them with your measurements and the specifications of your material.
Compare alternatives
Open a tool, enter your measured dimensions, then save an estimate. Keep another version if you want to compare products or allowances.