Calculator · Sheet T-210
Slope and grade converter
Convert percent grade, horizontal-to-vertical ratio and degrees, and find the rise over a distance.
STA 0+120How it works
Percent grade = rise ÷ run × 100. A ratio of H:1V is H metres horizontal per metre vertical, so grade = 100 ÷ H. Degrees = arctan(rise ÷ run). Rise over your distance = run × grade ÷ 100.
STA 0+240Assumptions and sources
Excavation cut-backs are written differently by province. Alberta measures from the vertical: at least 30° for hard, compact soil and 45° for soft or loose soil1. Ontario and Saskatchewan use ratios such as 1V:1H, and 1V:3H for Type 4 soil23. A slope measured 45° from vertical is the same as 1H:1V.
Questions people ask
How do you convert slope ratio to percent?
For a slope of H:1V, the grade is 100 ÷ H percent. A 4:1 slope is 25%; a 2:1 slope is 50%.
What is a 2% grade in degrees?
About 1.15°. Degrees = arctan(0.02).
What slope is required for an excavation?
It depends on the province and the soil type. Alberta’s minimum cut-back for soft or loose soil is 45° from vertical1; Ontario requires 1V:3H for Type 4 soil2. See trench safety.
Sources
- Alberta OHS Code (Alta Reg 191/2021), Part 32 Excavating and TunnellingGovernment of Alberta (OHS legislation search) · retrieved 2026-09-24
- O. Reg. 213/91 Construction Projects, Part III Excavations (ss. 222-242)Government of Ontario (e-Laws) · current to 2026-09-21
- The Occupational Health and Safety Regulations, 2020 (RRS c S-15.1 Reg 10), Part 17 Excavations, Trenches, Tunnels and Excavated ShaftsGovernment of Saskatchewan · as consolidated