Example 1
- Height difference: 0.6 m
- Horizontal distance: 6 m
Slope: 10.0%
Angle: 5.71°
This is a simple example showing the relationship between percentage slope and a relatively small angle.
Slope percent calculator
Type the height difference and the horizontal distance in the header unit. The calculator divides rise by run, multiplies by 100, and shows the angle. A 0.6 m drain on 6 m is 10.0% and 5.71°. A 1.2 m driveway on 8 m is 15.0% and 8.53°. A 0.35 m deck on 2.5 m is 14.0% and 7.97°.
A slope percentage calculator is useful for terraces, driveways, drainage, roofs, and any surface where the correct incline matters. It is a simple way to check whether the slope is sufficient and how it translates into an angle. Related: roof pitch angle, ridge height.
Results
Height difference (m) and Horizontal distance (m). The result shows up here.
How the results are calculated
Slope percent counts grade from two lengths. The formula is (height difference divided by horizontal distance) times 100. Angle is arctan(rise/run). Slope length, the hypotenuse, is √(rise²+run²). Both entries in the header unit, the result in percent and degrees.
A pipe or gutter dropping 0.6 m in 6 m is exactly 10.0% and 5.71°. A steeper 1.2 m driveway on 8 m is 15.0% and 8.53°. A short 0.35 m deck on 2.5 m is 14.0% and 7.97°. A roof with 2.8 m rise and 4.0 m half-span belongs on roof pitch: 34.99° and 70.0% there.
Type height difference and horizontal distance, both in the header unit. That is the level run, not the length along the slope. A comma in 0.6 works like 0,6. An empty run cannot make a percent, because there is nothing to divide by.
Roof angle from half-span and rise lives on roof pitch. Ridge height from an 8 m span at 35° and a 2.8 m wall is 5.60 m. The 3-4-5 ratio looks for 90°, not a grade percent.
One percent on 6 m is 6 cm of rise. Ten percent on the same run is 60 cm, as on the first card. Mixing centimeters of rise with meters of run breaks the scale: type 60 cm as 0.6.
Type 0.6 and 6, click Calculate, and match 10.0% and 5.71°. Then 1.2 and 8: 15.0% and 8.53°.
How to use this calculator
- Type the height difference in the header unit, for example 0.6. Sixty centimeters is 0.6, not 60.
- Enter the horizontal distance in the header unit, the run, for example 6. That is not the length along the slope.
- Click Calculate. 0.6 on 6 m is 10.0% and 5.71°. 1.2 on 8 m is 15.0% and 8.53°.
- Roof angle from half-span belongs on the roof pitch page, not here.
- The 3-4-5 ratio checks a right angle. This page stays slope percent.
A 10% grade on 0.6 m over 6 m
Rise divided by run, times 100. A 0.6 m drain on 6 m is 10.0% and 5.71°.
- %
- Slope percent. 0.6 / 6 × 100 = 10.0. A 1.2 m driveway on 8 m is 15.0%. A 0.35 m deck on 2.5 m is 14.0%.
- °
- Angle from arctan(rise/run). At 10.0% you get 5.71°. At 15.0% on the drive, 8.53°, not a 70% roof.
Example scenarios
Example 2
- Height difference: 1.2 m
- Horizontal distance: 8 m
Slope: 15.0%
Angle: 8.53°
For the same type of surface, an increase in slope percent quickly becomes a noticeably steeper incline.
Example 3
- Height difference: 0.35 m
- Horizontal distance: 2.5 m
Slope: 14.0%
Angle: 7.97°
On shorter sections, even a modest height change produces a visible percentage result.
Related calculators
FAQ
What slope is 0.6 m in 6 m?
10.0% and 5.71°. 0.6 / 6 × 100 = 10. The hypotenuse is √(0.36+36) ≈ 6.03 m.
What slope is 1.2 m in 8 m?
15.0% and 8.53°. A steeper driveway than the 10% on the first card.
What slope is 0.35 m in 2.5 m?
14.0% and 7.97°. A short deck, the same rise-over-run formula as a longer run.
How do I type 60 cm of rise?
As 0.6 m. Typing 60 in a meter field would be 60 m of rise.
Is the run the length along the slope?
No. The run is horizontal. Slope length is computed as √(rise²+run²).
How is 10% different from a 35° roof?
10% is 5.71°. A 2.8 on 4.0 m roof is 34.99° and 70% on the roof pitch page.
How many cm per meter at a 2% slope?
2 cm per meter of run. On 6 m that is 12 cm of rise.
Where do I get ridge height from an angle?
On ridge height. An 8 m span, 35°, and a 2.8 m wall give 5.60 m.
Does 3-4-5 replace this percent?
3-4-5 looks for 90°. Slope looks for rise over run. Two different cards.
What if the run is zero?
There is nothing to divide by. Horizontal distance must be greater than zero.
Knowledge sources
Volume and waste come from the sizes you type. Below are volume and NIST SI units.
Page updated in 2026.