Concrete Slab Calculator
Calculate concrete volume, rebar needs, and cost estimate for a slab.
Enter dimensions and reinforcement type for complete material estimates.
Concrete Slab Estimate
Concrete Slab Volume:
Volume (cu ft) = Length × Width × Thickness (all in feet)
Cubic Yards = Volume (cu ft) / 27
Cubic Meters = Length (m) × Width (m) × Thickness (m)
Rebar spacing guide:
| Slab Type | Rebar Size | Spacing |
|---|---|---|
| Sidewalk / Patio | #3 (3/8") | 18" on center |
| Driveway | #4 (1/2") | 12" on center |
| Garage Floor | #4 (1/2") | 12" on center |
| Structural | #5 (5/8") | 8–12" on center |
Rebar calculation:
- Bars along length:
(Width / Spacing) + 1 - Bars along width:
(Length / Spacing) + 1
Typical concrete costs (2024):
- Ready-mix delivery: $125–$165 per cubic yard
- Small jobs (bags): $5–$8 per 80-lb bag (~0.6 cu ft each)
Always order 10% extra for waste and uneven ground.