Inputs
Choose a mode, enter values, then press Calculate.
Example data
Sample inputs and expected gradient outputs for quick checking.
| Run | Start elev. | End elev. | Rise | Gradient (%) | Angle (deg) |
|---|---|---|---|---|---|
| 3000 m | 50 m | 62 m | 12 m | 0.40% | 0.23° |
| 8200 ft | 110 ft | 60 ft | -50 ft | -0.61% | -0.35° |
| 1800 m | — | — | 9 m | 0.50% | 0.29° |
Formula used
- Rise = End elevation − Start elevation
- Gradient (%) = (Rise ÷ Run) × 100
- Gradient (‰) = (Rise ÷ Run) × 1000
- Slope angle (degrees) = arctan(Rise ÷ Run) × (180 ÷ π)
- Ratio (1 in N) = |Run ÷ Rise| (shown as “1 in N”)
- Station elevation (linear) = Start elevation + Rise × (Station ÷ Run)
This calculator assumes a constant grade between endpoints. If your runway has vertical curves or multiple segments, compute each segment separately and compare.
How to use
- Select a unit system that matches your survey or design set.
- Choose a calculation mode: elevations or rise/run.
- Enter the runway length as a horizontal distance.
- Provide start/end elevations or the rise value.
- Optionally add a station distance to estimate elevation at that point.
- Press Calculate to view results above the form.
- Use Download CSV or Download PDF for records.
Tip: Negative rise means the runway falls from start to end. Use the “Your max grade” field to test against your internal design limit.