How thick should a garage floor be?

Four inches is typical for passenger vehicles on a well-compacted base. Five to six inches is often selected for heavy trucks, workshops, or vehicle lifts, but concentrated loads should be professionally designed.

How much concrete is needed for a 24 by 24 garage?

At 4 inches thick, the slab contains 192 ft³, or 7.11 yd³ net. With 10% waste, the suggested quantity is about 7.82 yd³ before adding footings or thickened edges.

Does the garage calculation include footings?

No. The calculator covers the rectangular floor slab. Perimeter footings, grade beams, stem walls, and equipment pads require separate volume calculations.

Garage Floor Concrete Calculator

Calculate concrete for a garage floor slab, including cubic yards with waste, concrete weight, bag equivalents, and an editable ready-mix material estimate.

Garage Floor Dimensions

Results update as you change the formed dimensions.

Length

Width

Slab thickness

Waste allowance

Ready-mix price

$/yd³

Order quantity

7.82yd³ with waste

Slab area

576ft²

Net volume

192ft³

Concrete weight

31,680lb · 15.8 tons

60 lb bags

470bags

80 lb bags

353bags

Estimated ready-mix material cost

$1,252

Includes $0 short-load fee when the order is under 3 yd³. Labor, base, forms, reinforcement, finishing, tax, and other delivery charges are excluded.

Garage Floor Concrete Thickness and Volume

Four inches is common for passenger-vehicle garage floors on a properly prepared base. Use 5–6 inches for heavy pickups, lifts, workshops, or concentrated equipment loads, subject to engineering and local code.

Garage floors may include thickened perimeter edges, interior footings, drains, or stem walls. Calculate those separately and add them to the slab quantity.

How to Calculate Concrete for a Garage Floor

Multiply the formed length by width and slab thickness after converting thickness from inches to feet. Divide cubic feet by 27 for cubic yards, then add the selected waste allowance.

Rectangular slab order

yd³ = length (ft) × width (ft) × [thickness (in) ÷ 12] ÷ 27 × (1 + waste%)

Measure the inside of the forms. Calculate thickened edges, footings, ramps, and separate pads independently.

Garage Floor Planning Checklist

Use the clear slab dimensions inside foundation or stem walls.
Add thickened edges, equipment pads, and interior footings as separate volumes.
Coordinate vapor barrier, insulation, reinforcement, drains, and door elevations before pouring.
Confirm the slab design for vehicle lifts or other concentrated loads.