How much gutter do I need?
Gutter is bought by the section, so the run of your eaves drives everything:
Sections = eave length ÷ section length, rounded up
Add up every roof edge that will get a gutter, then divide by your section length — usually 10 ft — and round up. On top of the gutter you add a downspout every 30–40 ft of run (at least one per run) and a hanger about every 2 ft to keep it from sagging.
Gutter parts you'll need
| Part | How many |
|---|---|
| Gutter sections | Eave length ÷ 10 ft |
| Downspouts | 1 per 30–40 ft of run |
| Hangers | 1 every ~2 ft |
| End caps & corners | Per run ends and each corner |
Good to know
- Slope toward downspouts. Pitch the gutter about 1/4 in per 10 ft so water drains instead of pooling.
- Size for the roof. 5-in K-style suits most homes; go 6-in with 3×4 downspouts for big or steep roofs.
- Send water away. Extend downspouts well past the foundation — or tie them into a French drain.
- Seal the joints. Sectional gutters need gutter sealant at every seam, end cap, and outlet.