Elevation Grade Calculator

This construction calculator converts rise and run into grade ratio, percentage, elevation angle, slope length, and a one-in-N ratio.

Formula notes

grade = rise / run; grade% = grade x 100; angle = atan(grade); slope length = hypot(rise, run); one-in-N = 1 / |grade|.

Worked examples

1. Example: a 1 m rise over a 20 m run is a 5% grade with about a 2.86 degree angle.
2. A 3 m rise over 15 m of run is a 20% grade with about an 11.31 degree angle and a 1-in-5 ratio.

How to use it

1. Enter the vertical rise and horizontal run.
2. Confirm the units for each measurement.
3. Read the grade ratio, percentage, angle, slope length, and one-in-N grade.

Frequently asked questions

Limits and interpretation

• The model uses a straight-line slope and ignores the curved or irregular path a real route may follow.
• The one-in-N value is rounded to two decimal places, so small grades can show coarse ratios.

References

• OpenStax College Algebra 2e