Gutters protect your foundation and landscaping from water damage, and getting the right length and number of downspouts keeps drainage working properly. This calculator sizes your gutter system based on roofline measurements.
Roof Details
ft
Scenario: Your home has 120 ft of roofline that needs gutters.
Result: You need 120 ft of gutter, 3 downspouts (one per 40 ft), and 40 hangers (one every 3 ft).
Install one downspout for every 30-40 feet of gutter run. Place them at the low end of each gutter section. More downspouts handle heavy rain better -- if you're in a high-rainfall area, use one every 20-30 feet.
5-inch K-style gutters handle most residential roofs. Use 6-inch gutters for roofs with steep pitches, large surface areas, or in areas with heavy rainfall. Half-round gutters are less common but hold more water per linear foot.
Space hangers every 3 feet for most climates. In areas with snow and ice, space them every 2 feet to handle the extra weight. Use hidden hangers (inside the gutter) for a cleaner look than external brackets.
Aluminum gutters: $4-$9 per foot installed. Vinyl: $3-$5 per foot. Copper: $15-$25 per foot. Seamless aluminum gutters (professionally installed) run $6-$12 per foot and are the most popular choice.
Want to learn more before you start your project?
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