About this tool Calculate slope grade, angle, and ratio using three input methods: rise and run, two survey levels with horizontal distance, or a known angle. The tool converts between all common slope representations used in earthworks and geotechnical design.
Results include percentage grade, angle in degrees, slope ratio (1:n), slope length, and direction (upslope/downslope). A reference table of common geotechnical slope ratios is included for cuttings and embankments in different ground conditions.
Unlike generic slope calculators, this tool uses survey-standard inputs (m AOD levels) and outputs the 1:n ratios that geotechnical engineers and earthworks designers actually work with.
How to use this tool 1. Choose your input method — rise & run for simple gradients, two survey levels for site data, or known angle for design checks.
2. Enter values in metres — rise can be negative for downslopes. For two-level mode, enter levels as m AOD and horizontal distance.
3. Read the results — all representations are calculated simultaneously. Use the slope ratio table to compare against typical design values.
Technical information Grade (%) = (rise / run) × 100
Angle (°) = arctan(rise / run)
Slope length = √(rise² + run²)
Common geotechnical ratios: 1:1 (45°, rock cuttings), 1:1.5 (33.7°, stiff clay), 1:2 (26.6°, general embankments), 1:3 (18.4°, soft ground), 1:4 (14°, landscaped slopes).
Limitations This tool calculates gradients for uniform slopes only. For slopes with variable gradients or benched profiles, calculate each section separately.
Slope ratios in the reference table are typical design values. Actual permissible slopes depend on ground conditions, drainage, surcharge loading, and must be verified by slope stability analysis for critical earthworks.
Revision history 21 April 2026: Initial release
Disclaimer This tool is provided for educational and general information purposes only. It is not a substitute for professional engineering advice, design or verification.
Diggy and its contributors are not licensed engineering consultants and no results generated by this tool should be used directly for construction, design or safety-critical decisions.
All values and outputs are based on published empirical correlations and should be independently checked and confirmed by a qualified geotechnical engineer before use.
By using this tool, you accept full responsibility for how you interpret and apply the information provided.
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