📐 Free calculator
Angle and gradient calculator
Enter the rise and the going to get the angle, the gradient as a ratio and a percentage, the sloping length and the cut angles. Choose “ramp” to check it against Approved Document M.
For planning and estimating only. Structural design, loads and compliance must be confirmed by a qualified engineer or designer.
Ramp limits (Approved Document M)
- 1:20 – flights up to 10 m going
- 1:15 – flights up to 5 m going
- 1:12 – flights up to 2 m going (the steepest allowed)
- No more than 500 mm rise in any one flight
Gradients between these points are interpolated. Anything gentler than 1:20 is treated as a level approach.
Questions
Frequently asked questions
1:12 for a flight of up to 2 m going under Approved Document M. Longer flights must be gentler, down to 1:20 for 10 m.
Take the inverse tangent of rise divided by going. 1:12 is about 4.8 degrees, 1:20 about 2.9 degrees.
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