Gutter Slope Calculator
Estimate total gutter drop, slope percentage, hanger quantity and installed-length cost from run length and a chosen slope rate.
Default project preview
2 in
Number of runs
2
Total gutter length
80 ft
Slope percentage
0.417%
Hangers per run
21
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Length per gutter run
Enter this project assumption in ft. The current imperial default is 40 ft.
Number of equal runs
Enter this project assumption in runs. The current imperial default is 2 runs. Minimum: 1.
Selected slope rate
Enter this project assumption in in per 10 ft. The current imperial default is 0.5 in per 10 ft.
Hanger spacing
Enter this project assumption in ft. The current imperial default is 2 ft.
Installed cost per length
Enter this project assumption in per ft. The current imperial default is 12 per ft. Minimum: 0.
How to read the outputs
Number of runs
equal-length gutter sections. Default preview: 2.
Total gutter length
run length × run count. Default preview: 80 ft.
Slope percentage
vertical drop ÷ horizontal run. Default preview: 0.417%.
Hangers per run
2 ft spacing. Default preview: 21.
Total hangers
including both run ends. Default preview: 42.
Installed allowance
total length × entered cost. Default preview: $960.00.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Imperial drop = run length ÷ 10 × inches per 10 feet. Metric drop = run length × millimetres per metre. Hangers = round up (run length ÷ spacing) + 1.
FAQ
Gutter Slope Calculator questions
Should a long gutter slope toward one or two outlets?+
That depends on roof runoff, outlet locations and system layout. Long runs are often divided around a high point.
Why calculate slope percentage?+
It provides a unit-independent way to compare the selected vertical drop with the horizontal run.
Does the calculator size the downspout?+
No. Use the downspout and roof-drainage calculators for preliminary runoff capacity.