Drop per foot
Gutter Slope Per Foot
See exactly how much a gutter drops for each foot of run, and turn that per-foot slope into a total drop, a grade percentage and a 1:X ratio.
Slope per foot & marking table
Live
Cumulative drop along the run
Slope per foot
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Per foot
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Per 10 ft
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Grade
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mm per metre
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Gutter slope per foot is the vertical drop built in for every single foot of horizontal run. It is the most practical way to mark out a gutter, because you can read the drop at any point along a chalk or string line. The default here, 1/16 in per ft (0.0625 in/ft), is a popular residential slope; the minimum, 1/4 in per 10 ft, works out to just 0.025 in/ft.
Quick reference
Slope per foot, side by side
| Per foot | Per 10 ft | Grade | mm per m | Drop over 30 ft |
|---|---|---|---|---|
| 0.025 in/ft | 1/4 in | 0.21% | 2.1 mm/m | 0.75 in |
| 0.05 in/ft | 1/2 in | 0.42% | 4.2 mm/m | 1.50 in |
| 0.0625 in/ft | 5/8 in | 0.52% | 5.2 mm/m | 1.88 in |
| 0.125 in/ft | 1‑1/4 in | 1.04% | 10.4 mm/m | 3.75 in |
| 0.25 in/ft | 2‑1/2 in | 2.08% | 20.8 mm/m | 7.50 in |
Interactive — pick a per-foot slope, drag the run
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Marking it out
Using slope per foot on the wall
Interactive — mark the slope along the wall
Frequently asked
Questions answered
How much slope per foot does a gutter need?
The widely used minimum is 1/4 inch of drop for every 10 feet, which is 0.025 inch per foot. A common residential target is 1/16 inch per foot (0.0625 in/ft). Anything in that band drains well without looking visibly tilted.
What is 1/4 inch per 10 feet in slope per foot?
Divide 0.25 inch by 10 feet to get 0.025 inch per foot. That is the per-foot drop you mark out as you move along the run: 0.025 in at 1 ft, 0.05 in at 2 ft, and so on.
How do I work out the total drop from slope per foot?
Multiply the per-foot slope by the run in feet. A 30 ft gutter at 0.0625 in/ft drops 30 × 0.0625 = 1.875 inches end to end. The Drop mode does this instantly and also shows it in mm and as a grade.
Is more slope per foot always better?
No. Past about 1/4 inch per foot the gutter looks crooked next to the fascia and water can overshoot the outlet. Stay near the typical band unless a long run or heavy rainfall calls for more.
How is slope per foot related to grade percentage?
Grade percent equals slope per foot divided by 12, times 100. So 0.0625 in/ft is 0.0625 ÷ 12 × 100 = 0.52% grade. The calculator shows both for every result.
Need the full gutter slope toolkit?
Switch between drop, slope check, max run and downspout planning on the main calculator — with the same live diagram.