What is grade percentage in surveying?

Grade percentage (also written as % grade or % slope) is the vertical rise divided by the horizontal run, multiplied by 100. A 10% grade means the ground rises 10 meters for every 100 meters of horizontal distance.

How do I convert grade percentage to degrees?

Use the formula: degrees = arctan(grade% / 100). For example, a 10% grade equals arctan(0.10) ≈ 5.71 degrees. This calculator does that conversion instantly.

What does a 1:20 ratio mean?

A 1:20 ratio means the slope rises 1 unit vertically for every 20 units horizontally. This equals a 5% grade and approximately 2.86 degrees — a common accessibility ramp standard.

What is a steep grade for a road?

Roads steeper than 8–10% are considered steep for standard vehicles. Mountain roads sometimes reach 15%. Grades above 20% are rarely used for public roads but may appear on private driveways or rail inclines.

Is grade the same as slope?

Grade and slope describe the same thing but grade is usually expressed as a percentage, while slope may also be expressed as an angle in degrees or as a dimensionless ratio. This tool converts freely between all three.

What grade is a 45-degree slope?

A 45-degree slope is a 100% grade, meaning the rise equals the run. This is extremely steep — steeper than most ski runs and essentially a cliff for vehicles.

Grade Percentage Survey Calculator

Name: Grade Percentage Survey Calculator
Availability: InStock
Author: Nham Vu

Convert between slope grade percentage, degrees, and rise-over-run ratio instantly for surveying and road design.

Enter Any One Value

Type in one field — the other two update automatically.

Grade Percentage (%)

Angle (Degrees)

Ratio (1 : X — horizontal per unit rise)

1 :

Conversion Results

Enter a value on the left to see results.

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Summary

Convert between slope grade percentage, degrees, and rise-over-run ratio instantly for surveying and road design.

How it works

Enter a value in any one of the three fields: grade percentage, degrees, or ratio.
The calculator instantly converts and fills the other two fields.
Grade percentage is rise divided by run multiplied by 100.
Degrees are derived using the arctangent of (rise / run).
Ratio (1:X) expresses how many horizontal units correspond to 1 unit of rise.
Click Reset to clear all fields and start a new conversion.

Use cases

Convert road gradient percentages to angles for civil engineering drawings.
Check if a slope meets accessibility ramp requirements (typically 5% or less).
Calculate steepness of terrain from surveying field notes.
Design drainage channels and verify minimum fall gradients.
Convert between the notation systems used by different countries or standards.
Verify hillside driveway grades before construction.
Assess ski slope or hiking trail steepness.
Convert survey stake gradient markings to degrees for angle-setting equipment.

Frequently Asked Questions

Last updated: 2026-06-24 · Reviewed by Nham Vu