SiteCalculators
  1. Home
  2. Calculators
  3. Gradient Converter

Free site calculator

Gradient Ratio, Percentage, Degrees and mm/m Converter

Convert any gradient between 1:n ratio, percentage, degrees and millimetres per metre, with the change over ten metres.

Enter your data

Choose one known gradient representation and verify the fall direction separately from its magnitude.

No sign-in
1 : n
Inputs are processed in this browser. This calculator does not send project data to a server.
Conversion limitation: This converts gradient magnitude only. Confirm the actual rise or fall direction, horizontal-distance convention, design criteria and required rounding separately.

Equivalent gradient formats

A 1:n ratio means one unit of vertical change over n units horizontally. Percentage is vertical change divided by horizontal distance multiplied by 100. Millimetres per metre is the same slope multiplied by 1,000.

percentage = 100 ÷ n
mm per metre = 1,000 ÷ n
degrees = atan(1 ÷ n)

Signs and direction

The converter preserves signs for percentage, degrees and millimetres per metre. On drawings, gradients are often written as a positive magnitude with a separate arrow showing the fall direction.

Frequently asked questions

What is 1:80 as a percentage?

It is 1.25 percent, equivalent to 12.5 mm of vertical change per horizontal metre.

Is a 10 percent gradient the same as 10 degrees?

No. Ten percent is approximately 5.71 degrees because percentage is based on tangent, not a direct degree conversion.

How is a level gradient displayed?

Zero percentage, zero degrees and zero mm/m correspond to an infinite ratio denominator, shown as 1:∞.