Enter your slab dimensions and thickness to get concrete volume in cubic yards, number of bags needed, and estimated cost.
The Square Yard Concrete Calculator is used to quickly calculate key measurements and estimates so you can plan materials, costs, and project scope with confidence.
Measure the length and width of your concrete project in feet, yards, or meters. For irregular shapes, break the area into rectangles and use our Irregular Shape Calculator first.
Standard patios and sidewalks use 4 inches. Driveways need 4-6 inches. Garage floors and heavy-traffic areas require 6 inches. Foundations are typically 8-12 inches. Use our preset buttons for quick selection.
Always add 5-10% extra for waste, spillage, and uneven ground. Our calculator defaults to 10% — adjust as needed based on your project's complexity.
A 10 ft × 12 ft patio at 4" thick: Area = 120 ft² = 13.33 yd². Volume = 120 × (4/12) = 40 ft³ = 1.48 cubic yards. With 10% waste = 1.63 yd³ ≈ 74 bags of 80-lb concrete.
Understanding the relationship between area and volume.
Square yards measure flat area (2D), while cubic yards measure volume (3D). To go from area to volume, you multiply the area by the depth/thickness of your concrete slab. This calculator handles the conversion automatically.
One cubic yard of concrete covers 27 square feet at 12 inches deep, 54 square feet at 6 inches deep, or 81 square feet at 4 inches deep. The thinner the slab, the more area one cubic yard covers. That's why thickness is the most important variable after area.
Ready-mix concrete is sold by the cubic yard for truck delivery (minimum 1 yard for most suppliers). Bagged concrete (60-lb and 80-lb) is better for small projects under 1 cubic yard. Our calculator shows both options so you can choose the most cost-effective approach.
Common questions about concrete estimation.
Multiply the area in square yards by the thickness in yards. For example, 20 yd² × 4 inches (0.111 yards) = 2.22 cubic yards of concrete.
You need approximately 45 bags of 80-lb concrete mix to make 1 cubic yard. Each 80-lb bag yields about 0.6 cubic feet, and 1 cubic yard = 27 cubic feet.
Standard sidewalks: 4 inches. Patios: 4 inches. Driveways: 4-6 inches. Garage floors: 6 inches. Foundations: 8-12 inches. Always check local building codes.
Yes, always order 5-10% extra concrete to account for spillage, uneven ground, and slightly thicker-than-planned areas. Our calculator includes a waste factor option.
Ready-mix concrete typically costs $125-$150 per cubic yard delivered, plus $50-$65 per yard for pumping. Prices vary by region and the mix design you need.