Slope to ° Converter

Convert Slope to Angle instantly.

Free online converter with accurate results and clear explanations.

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How This Tool Works

The Slope to Angle Converter turns a slope ratio into the angle it makes with the horizontal plane. Slope is rise divided by horizontal run, which matches the tangent of the angle.

The calculator applies the inverse tangent formula: angle = arctan(slope). For example, a slope of 0.75 means 3 units of rise for every 4 units of run, which is about 36.87°.

  • Input: Slope as a decimal, percent grade, or 1:N ratio.
  • Formula: angle = arctan(slope).
  • Output: Angle in degrees, DMS, percent grade, and equivalent ratio.

Why This Matters

Slopes and angles describe the same steepness in different formats. Converting between them helps compare road grades, ramps, terrain, roof pitches, and engineering drawings that use different conventions.

  • Civil engineering: Check ramp, drainage, and roadway grades against angle-based specifications.
  • Physics: Use the angle of an inclined plane when resolving forces and acceleration.
  • Surveying and mapping: Translate measured grade into a geometric angle for plans and terrain notes.

Common Mistakes to Avoid

  • Use horizontal run: Slope compares rise to horizontal distance, not the sloped surface length.
  • Convert percent first: A 50% grade is a slope of 0.5, not 50.
  • Keep ratio direction clear: A 1:2 ratio means 1 unit of rise for 2 units of horizontal run.

Frequently Asked Questions

Common questions about the Slope to ° Converter

Enter your Slope value in the input field, and the converter will automatically calculate the equivalent Angle value. You can also click the swap button to reverse the conversion direction.

Sources & References

International System of Units (SI): plane angle

Plane angle is measured in the radian (rad); 1° = π/180 rad. Conversions between SI and other units use exact, internationally agreed factors maintained by NIST.

International System of Units (SI)

Authoritative definitions for plane angle, from the BIPM SI Brochure (9th edition), the defining reference for the SI.