Slope Calculator
Find percent grade and angle from rise and horizontal run, or solve a missing rise or run. Mix length units and inspect a labelled elevation diagram.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Convert rise and horizontal run into meters before dividing. Grade is 100 times rise/run; angle is arctan(rise/run). For a known angle, use its tangent as rise/run. Calculate inclined length with the Pythagorean theorem.
m = rise/run; grade (%) = 100m; angle = atan(m); rise = run × m; run = rise/m
Worked example
A rise of 1 m over a horizontal run of 10 m gives 10% grade, about 5.710593° and inclined length about 10.049876 m. A 45° angle corresponds to 100% grade.
Assumptions and input details
Run is horizontal distance, not distance along the incline, and must be positive. Negative rise means descending. A 10% grade is not 10 degrees. The ratio is displayed as vertical:horizontal; any 1:n entry also states ascent or descent. A zero slope cannot uniquely solve run. This geometry tool does not assess building-code compliance, accessibility, structural strength or safe gradients.
References: OpenStax: linear functions · OpenStax: slope
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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