How this calculator works
Grade compares vertical rise with horizontal run. Percent grade is 100 times this ratio. Use plan distance rather than the measured sloping length. Angle-only mode shows the rise over a reference run in metres.
Formula
grade = rise / run; percent grade = 100 x grade; theta = atan(grade); rise = grade x run.
Worked example
A 1 m rise in 20 m of horizontal travel gives grade 0.05, or 5%, and an angle of 2.8624 degrees.
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Frequently asked questions
Is 100% grade vertical?
No. It means equal rise and run, giving 45 degrees.
Can I enter a downhill grade?
Yes. Use a negative elevation change or grade, while horizontal distance stays positive.
Is this a drainage design check?
It is a geometric conversion. Drainage and accessibility limits depend on the applicable design requirements.