Concrete Slab Calculator
Calculate concrete for a slab by dimensions. Cubic yards, bags, and rebar spacing. Free calculator.
Slab Thickness Guide
Patios/sidewalks: 4 inches. Driveways (cars): 4-5 inches. Driveways (trucks): 5-6 inches. Garage floors: 4-6 inches with wire mesh. Always pour over 4+ inches of compacted gravel for drainage. Include control joints every 8-10 feet — concrete cracks, but joints control where.
Reinforcement Requirements
Driveways and garages: #4 rebar on 18-inch centers or welded wire mesh. Rebar sits at mid-depth using chairs. Patios under foot traffic need wire mesh only. Any slab supporting vehicles needs rebar — the cost difference is $50-100 per project but the structural improvement is massive.
Concrete reaches 70% of its strength in 7 days but needs 28 days to fully cure. Do not drive on a new driveway for at least 7 days. Walking is fine after 24-48 hours.
