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The slope angle from horizontal, in degrees.
Measured with an inclinometer or digital level. Check several points along the run — a single reading can sit on a local high or low spot.
Gradient
8.749 %
Percent = tan(angle) × 100. 100% is a 1:1 slope, not vertical — percentages become unhelpful once gradients get steep.
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Slope Degrees to Percent Calculator: 8.75 % — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Gradient percentage = tan(angle) x 100
Inputs used
- Slope angle (°)
- 5
Confidence note: Percent = tan(angle) × 100. 100% is a 1:1 slope, not vertical — percentages become unhelpful once gradients get steep.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-08-26 · in the site-wide review of 2026-09-06 · v1.0.0
Regulatory standards & verification citations1
- Gradient percentage = tan(angle) x 100
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Surveying an existing fall gives degrees, while civil drawings, drainage schedules and paving specifications want a percentage. The conversion is a tangent, and the useful thing to understand is where it stops behaving intuitively. At shallow gradients percentage and degrees run almost in step; by 45 degrees the gradient reads one hundred percent, which is a 1:1 slope rather than anything approaching vertical. That is why percentages are the natural unit for drainage and ramps and a poor one for roofs. On site, take readings at several points along the run rather than one: compliance usually depends on no section falling below the minimum, not on the average clearing it.