How Much Gutter Do I Need?
Quick answer: measure every horizontal roof edge that drains water and add the runs together — a typical 2,000 sq ft house needs 180–220 linear feet of gutter. Then plan one downspout every 30–40 ft (never more than 50 ft per run), which works out to about 5 downspouts for that house.
- Measuring gutter linear feet
- How many downspouts
- 5-inch vs 6-inch gutters
- Worked example: 2,000 sq ft house
- Common mistakes
- FAQ
Measuring gutter linear feet
Gutter is priced by the linear foot of horizontal run. Walk around the house and measure every roof edge where a gutter will collect water — usually that's the eaves on the front and back of the house plus any low sides. Gable ends without eaves don't get gutters. For a rectangular two-story house, the guttered runs are typically one long side plus the two short sides; the matching long side on the back adds the same again if it has a drip edge.
How many downspouts
Downspouts carry the water down. The standard spacing rule: one downspout every 30–40 ft of gutter run, maximum 50 ft. Always put one near each outside corner. On a 40 ft front run, one downspout at the corner plus one in the middle keeps the gutter from overflowing in a downpour. More downspouts cost a little more but reduce overflow risk on long runs.
5-inch vs 6-inch gutters
Most US homes use 5-inch seamless gutters, which drain roughly a 1-inch rainfall per hour on a typical roof. 6-inch gutters carry about 40% more water and are the right upgrade for steep roofs, heavy-rain regions, or roofs with large valleys. A simple guide: if your roof's drainage area (footprint plus 50% for steepness) exceeds about 2,500 sq ft, or your area sees intense storms, go 6-inch.
Worked example: a 2,000 sq ft two-story house
- Front eave = 60 ft, back eave = 60 ft, two side runs = 30 ft + 30 ft
- Total gutter = 180 linear feet
- Downspouts: 60 ft front ÷ 30–40 ft = 2; back = 2; plus 1 for the side valley = 5 downspouts
- Gutter size: 5-inch is fine for this roof; upgrade to 6-inch in heavy-rain zones
Common mistakes
- Guttering the gable ends. Those walls don't have a drip edge — measure only actual eaves runs.
- Under-counting downspouts on long walls. A 50 ft run with one downspout will overflow in heavy rain. Stay at 30–40 ft spacing.
- Ignoring valleys. Valleys collect water from two roof planes; a downspout at each valley outlet is non-negotiable.
- Buying 5-inch for a huge roof. If the drainage area tops ~2,500 sq ft or your storms are intense, 6-inch is the fix — cheap now, expensive retrofit later.
FAQ
One downspout for every 30–40 ft of gutter run (never more than 50 ft). A 2,000 sq ft house with about 180 linear feet of gutter needs roughly 5 downspouts.
About 180–220 linear feet of gutter for a typical 2,000 sq ft two-story house. Measure every roof edge where water drains.
Space downspouts 30–40 ft apart for 5-inch gutters, up to 50 ft maximum on a straight run. Put one near each corner.
5-inch gutters handle most homes, but 6-inch gutters carry about 40% more water and are the right call for steep roofs, heavy-rain regions, or long valleys.
Measure each horizontal run along the eaves where a gutter will sit and add them up. Don't include gable ends with no gutter.