Calculate rise, gradient and slope angle from map measurements.
Gradient = elevation change ÷ horizontal ground distance. Count intervals between contours, not the number of contour lines (six successive lines span five intervals). Use the elevation difference between your endpoints; counting a route that crosses up and down gives a misleading result. The distance must be horizontal, not distance along the slope. Results describe average steepness, not terrain safety.
Instructions
- Choose Calculate elevation change from and enter the known rise or contour intervals.
- Select Elevation unit. Count the spaces between contour lines when using intervals.
- Choose Horizontal distance measured on, then enter Horizontal distance with the relevant ground or map units and scale.
- Select Calculate and use Download results or Print.
Understanding your results
A 100 m rise over 1,000 m horizontally is a 10% gradient. Slope angle expresses that same relationship in degrees. This averages the slope between endpoints and can hide a much steeper short section along the route.
What to do if your gradient seems too steep
Check you counted contour intervals rather than lines, and used horizontal distance rather than a sloping tape measurement. If the route climbs and descends, use the endpoint elevation difference for this calculation rather than adding every crossing.
Using this tool in your browser
This tool handles your entries in your browser with JavaScript enabled and does not save them automatically. Use the download or print controls described in the instructions to keep a copy before closing or reloading the page. On a phone, your browser controls where downloads go and which print options are available.
Summary
Use the result to understand average steepness alongside the actual contour pattern and terrain.