%
Drainage Slope Calculator
Calculate drainage slope percentage from fall and run.
Safety and professional-use note
Civil engineering calculators on ToolsBing are preliminary estimating tools only. Verify dimensions, material properties, safety factors, local building codes, site conditions, and structural requirements with a qualified professional before construction, procurement, or design approval.
Enter civil engineering inputs
Estimated result
Use for early-stage sizing and procurement checks only.
Confirm measurements, material standards, and local code requirements.
Formula and assumptions
Slope % = (fall ÷ run) × 100
This calculator uses simplified assumptions so users can estimate quickly. Adjust real projects for waste, compaction, reinforcement, design loads, site condition, and professional engineering requirements.