Free Concrete Slab Calculator
Calculate Concrete Volume for Slabs in Cubic Yards
Patio: 4″, Driveway: 5-6″
📋 How to Calculate Slab Concrete
- Volume (cu ft) = L × W × (T ÷ 12)
- Cubic Yards = Volume ÷ 27
- 80lb Bags = Cu Yd × 45
❓ Slab Calculator FAQ
How do you calculate concrete for a slab?
L × W × (T/12) = cu ft. ÷ 27 = cu yd. Formula: Cu Yd = (L × W × T/12) ÷ 27
How many yards for a 20×20 slab?
20’×20’×4″ = 4.94 cu yd (133 cu ft). About 223 bags of 80lb concrete.
How thick should a concrete slab be?
Patios: 4″. Driveways: 4-6″. Garage: 4-6″. Foundations: 6-8″.
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