Concrete Ramp Calculator

Calculator built by BuilderToolkits | Updated February 2026

Estimate concrete ramp volume using length, width, rise, and waste factor. This concrete ramp calculator returns cubic yards, cubic feet, and 80‑lb bag counts for quick takeoffs. For slab pours, use the Concrete Slab Calculator. For reinforcement and subbase planning, use the rebar estimator and the gravel base calculator.

Inputs

Slope guidance

ADA guidance is 1:12 (1 inch of rise for every 12 inches of run). A typical driveway slope range is roughly 8–12% depending on site conditions.

Current slope: 8.33%

Results

Concrete volume
2.44 yd³
66 ft³ total
Includes 10% waste.
80-lb bags (rough)
110 bags
Assumes ~0.6 ft³ yield per 80-lb bag (varies by mix).

Assumptions

  • Ramp is a straight triangular prism with uniform width.
  • Waste factor covers form loss, spillage, and over-excavation.
  • 80-lb bag yield is an approximation; verify product labels.

Next Steps

✓Round up to the nearest 0.25 yd³ for ready-mix orders.
✓Estimate reinforcement with the rebar estimator.
✓For slab or pad volumes, use the concrete slab calculator.

Example

A 12 ft × 10 ft ramp with 1 ft rise and 10% waste needs about 2.44 yd³ of concrete.

How to Calculate a Concrete Ramp (Formula)

Volume (ft³): Length (ft) × Width (ft) × Rise (ft) ÷ 2

Cubic yards: Volume (ft³) ÷ 27 × (1 + Waste %)

FAQ

How steep can a concrete ramp be?

ADA guidance is 1:12 (1 inch of rise per 12 inches of run). Many driveways are steeper, but gentler slopes improve traction and drainage control.

What thickness for ramps?

Many residential ramps are 4–6 inches thick, with thicker sections for heavy vehicles. Check local requirements or engineering for load-bearing ramps and confirm subbase compaction with the gravel base calculator.

Do ramps need rebar?

Most concrete ramps benefit from reinforcement to control cracking. Use the rebar estimator to plan quantities, and verify spacing with local code or engineering.

How long should ramp be?

Ramp length depends on rise and target slope. A 1:12 slope needs 12 feet of run for every 1 foot of rise.

How much concrete for garage ramp?

Use the ramp length, width, and rise to calculate volume, then add waste. For bag ordering, use the concrete bag calculator.

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