Calculate concrete for slabs — cubic yards, cubic feet, and 80 lb bag count for patios, driveways, garage floors, and shed pads.
Enter your slab dimensions to calculate concrete needed.
A concrete slab calculator uses length, width, and thickness. Convert thickness from inches to feet, then divide the total cubic feet by 27.
Slab thickness varies by application. Patios and sidewalks use 4 inches. Driveways need 5-6 inches for vehicle loads. Garage floors use 4-6 inches depending on expected weight.
At 4 inches thick, 1 cubic yard covers about 81 square feet. At 6 inches, coverage drops to 54 square feet per yard. Use this to estimate orders quickly.
Always round up. Ready-mix trucks deliver in quarter-yard increments. Short loads under 5 yards may incur extra charges. Add 10% waste for uneven subgrade.
4 inches for patios and sidewalks, 5-6 inches for driveways, and 6+ inches for heavy loads like commercial floors.
At 4 inches thick, 1 cubic yard covers about 81 square feet. At 6 inches, about 54 square feet.
A 10×10 ft slab at 4 inches thick needs about 1.23 cubic yards. With 10% waste, order 1.4 cubic yards.
| Application | Minimum | Recommended | Strength (PSI) |
|---|---|---|---|
| Sidewalk / Path | 3.5 inches | 4 inches | 3,000 |
| Patio | 4 inches | 4 inches | 3,000-3,500 |
| Residential Driveway | 4 inches | 5-6 inches | 3,500-4,000 |
| Garage Floor | 4 inches | 6 inches | 3,500-4,000 |
| Commercial Parking | 6 inches | 6-8 inches | 4,000-4,500 |
4 inches for sidewalks and patios, 5-6 inches for driveways and garage floors, 6-8 inches for commercial applications. Check local building codes.
At 4 inches: 1.23 CY. At 6 inches: 1.85 CY. Add 10% for waste, so order about 1.4 or 2.0 CY respectively.
Recommended for all slabs over 4 inches and required for driveways, garage floors, and vehicle traffic areas. Reinforcement prevents cracks from spreading.
A standard 4-inch slab costs - per sq ft installed. Thicker slabs and decorative finishes increase costs to - per sq ft.
4-6 inches for standard slabs (patios, sidewalks) and 6-8 inches for driveways. Compact in lifts; never pour concrete over loose base material.
Wait 24-48 hours for foot traffic, 7 days for heavy loads. Full strength at 28 days. Avoid vehicles for at least 7-10 days.
Expertise covers cubic yard and square yard formulas, material quantity planning, unit conversions, and practical ordering checks for home and contractor projects.