Slope Gradient Converter

Convert between slope percent, angle in degrees, radians, and rise-over-run style gradient ratios for construction, road, and accessibility work.

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Slope and gradient converter Convert a ramp, road, roof pitch, or terrain angle between percent grade, a 1:N ratio, degrees, and radians.

Common presets

How to read 1:N

A 1:N ratio means one unit of rise for every N units of horizontal run. Larger N values are shallower grades.

Quick checkpoints

100% grade = 45°. A 1:12 ramp is about 8.33%. Zero grade is level and has no finite 1:N ratio.

Enter a value Provide a percent, ratio, degree, or radian slope to compare every representation side by side.

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Slope Converter

Slope and gradient converter: percent grade, degrees, radians, and rise-over-run explained

A slope and gradient converter turns the same incline into the language used by drawings, accessibility guidance, road design, and site work. Enter a percent grade, an angle, a radian value, or a rise-over-run ratio and compare the equivalents without doing the trigonometry by hand.

How slope formats connect

Percent grade describes rise divided by horizontal run, multiplied by 100. A 10% grade means 10 units of rise for every 100 units of horizontal run. Angle uses the same geometry, but it expresses the incline as a rotation from horizontal instead of as a ratio.

Because those formats are linked by the tangent function, they are not linearly interchangeable. Doubling the angle does not simply double the percent grade.

Percent grade = (rise / run) × 100

Standard way to express slope as a percentage of horizontal run.

Angle = arctan(rise / run)

Converts a geometric ratio into an angle from horizontal.

1:12 = 8.33% ≈ 4.76°

A familiar accessibility example showing ratio, percent, and angle for the same incline.

Where percent grade and ratios appear

Percent grade is common in roads, ramps, drainage, trail design, and site plans because it communicates steepness in a compact way. Ratios such as 1:12 or 1:20 stay common in accessibility and construction guidance because they show the relationship between rise and horizontal run directly.

Degrees and radians are more common in mathematics, surveying, and engineering calculations where the incline needs to connect to trigonometric formulas or instrument readings.

Running slope versus other measurements

Slope ratios should always describe rise over horizontal run, not rise over the sloped path length. That distinction matters because using the wrong base length will understate the real grade.

Accessibility references also distinguish running slope from cross slope. The same site can meet one requirement and fail the other, so this converter should be treated as a geometry helper rather than a standalone compliance decision.

Further reading

Frequently asked questions

Is percent grade the same as degrees?

No. Percent grade is a rise-over-run ratio scaled by 100, while degrees express the incline as an angle. They are connected through trigonometry, so the relationship is curved rather than linear.

 What does 1:12 mean?

It means 1 unit of rise for every 12 units of horizontal run. That corresponds to about 8.33% grade and roughly 4.76 degrees.

 Why does a small change in degrees matter more on steep slopes?

Because the tangent relationship gets steeper as the angle rises. Near-horizontal angles change percent grade slowly, but at steeper inclines the same angle change can produce a much larger grade jump.

 Can I use this to prove accessibility compliance?

Use it as a geometry check only. Real compliance also depends on which slope is being measured, the applicable standard, and the physical context of the route or ramp.

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