Ramp calculator
Work out a ramp's gradient, and check it against the steepest the building regulations' guidance allows for its length.
Limits from Approved Document K, on GOV.UK.
Result
A rise of 300 mm over 5 m is a gradient of 1 in 16.7, within Approved Document K's limit of 1 in 15 for that going.
| As a percentage | 6% |
|---|---|
| As an angle | 3.43° |
| Steepest for this going | 1 in 15 |
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Gradient, 1 in | 5,000mm going ÷ 300mm rise | 16.667 |
| Steepest Approved Document K shows for this going | between 1:12 at 2m and 1:15 at 5m | 15 |
Where the figures come from
- Ramp going for gradient point 1: 2 m. Source: Approved Document K: protection from falling, collision and impact, 2013 edition (GOV.UK). Checked 13 November 2026.
- Steepest ramp gradient (1 in N) at that going: 12 1 in. Source: Approved Document K: protection from falling, collision and impact, 2013 edition (GOV.UK). Checked 13 November 2026.
- Ramp going for gradient point 2: 5 m. Source: Approved Document K: protection from falling, collision and impact, 2013 edition (GOV.UK). Checked 13 November 2026.
- Steepest ramp gradient (1 in N) at that going: 15 1 in. Source: Approved Document K: protection from falling, collision and impact, 2013 edition (GOV.UK). Checked 13 November 2026.
- Ramp going for gradient point 3: 10 m. Source: Approved Document K: protection from falling, collision and impact, 2013 edition (GOV.UK). Checked 13 November 2026.
- Steepest ramp gradient (1 in N) at that going: 20 1 in. Source: Approved Document K: protection from falling, collision and impact, 2013 edition (GOV.UK). Checked 13 November 2026.
How steep can a ramp be?
Approved Document K links the steepest gradient to the ramp's going, its length between landings. A short ramp may be steeper than a long one:
- A going of 2 m: no steeper than 1 in 12.
- A going of 5 m: no steeper than 1 in 15.
- A going of 10 m: no steeper than 1 in 20.
Between 2 m and 10 m it is acceptable to work out the limit in between, so a 4 m going may be 1 in 14 and a 9 m going 1 in 19. A floor that slopes at 1 in 20 or steeper should be designed as a ramp.
Approved Document M adds more for access to buildings, such as landings and handrails. Approved Documents are guidance: your building control body decides whether work meets the regulations.