Concrete Depot
Concrete Calculators & Tools
Dashboard-ready report tool

Concrete Slab Slope Calculator

Calculate slab slope, total fall, slope ratio, angle, concrete volume, bag count, cost, and a branded report with a live 3D slope diagram.

Measurement inputs

Live calculation
Used in the saved report.
Switches dimensions and report units.
Use waste volume when ordering bags.
Horizontal run in slope direction. Enter a run length greater than 0.
Width across the slab. Enter a slab width greater than 0.
Use average thickness if the slab is wedge-shaped. Enter a thickness greater than 0.
Vertical fall from high side to low side. Enter a fall value of 0 or more.
Common values: 5%, 10%, or 15%. Waste cannot be negative.
Optional. Leave blank if cost is not needed. Cost cannot be negative.

Result dashboard

Rounded estimates
Calculated slab slope
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Enter valid measurements to calculate slab slope and concrete quantity.
Slope ratio—
Slope angle—
Fall per foot—
Total fall—
Base volume—
Order with waste—
60 lb bags—
80 lb bags—
Slab area—
Cubic feet—
Cubic meters—
Estimated cost—

Formula used

Shown in report
Slope (%) = Total fall ÷ Run length × 100
Angle = atan(Total fall ÷ Run length)
Concrete volume = Length × Width × Slab thickness
  1. Enter valid values to see the full calculation steps.

Volume uses slab thickness. The slope changes the fall across the slab. If your slab thickness changes from one end to the other, use the average thickness in the thickness field.