Treadmill incline calculator
Written by Jamie Miller, Founder & EditorLast checked
Treadmill incline is measured in percent grade, not degrees, and the two are easy to confuse. A 10% incline is about 5.7° — a genuine hill, not the steep ramp "10%" might suggest. Percent grade is rise over distance travelled; degrees is the angle itself, and they only match closely at very low inclines.
Percent to degrees
| Incline (%) | Degrees | Feel |
|---|---|---|
| 0% | 0.0° | Flat |
| 1% | 0.6° | Barely noticeable |
| 2% | 1.1° | Barely noticeable |
| 3% | 1.7° | Barely noticeable |
| 4% | 2.3° | Gentle hill |
| 5% | 2.9° | Gentle hill |
| 6% | 3.4° | Gentle hill |
| 7% | 4.0° | Genuine hill |
| 8% | 4.6° | Genuine hill |
| 9% | 5.1° | Genuine hill |
| 10% | 5.7° | Genuine hill |
| 12% | 6.8° | Steep |
| 15% | 8.5° | Steep |
The formula
degrees = arctan(percent ÷ 100) × 180 ÷ π
Percent grade is rise divided by horizontal distance, expressed as a percentage. A treadmill displaying its incline in percent is describing that ratio directly; converting to degrees is the trigonometric angle whose tangent equals that ratio. The relationship is not linear, which is why a jump from 20% to 30% incline is a much bigger change in angle than 0% to 10%.
Related: incline treadmills, what the number means in practice