About Concrete & Driveways Calculations
Concrete is sold by the cubic yard, and that's where most ordering mistakes happen. You measure a slab in feet and inches, but the plant talks in yards. One cubic yard fills 27 cubic feet, or an 80 square foot slab at 4 inches thick. Get the conversion wrong and you're either short with the truck already pouring, or paying for concrete you dump.
For flatwork, order about 5 to 10% over your calculated volume. Forms bow, subgrade isn't perfectly level, and you don't want the truck to run dry three feet from the edge. A short-load fee plus a second truck costs far more than a little overage.
Asphalt works in tons, not yards. Standard hot mix runs around 145 pounds per cubic foot, so square footage and depth convert to tons through that weight. Compaction eats a little, so order slightly heavy.
Depth matters more than people think. A residential driveway wants 4 inches of concrete or 2 to 3 inches of asphalt over a compacted base. Skimp on either and you'll see cracks within a couple of winters. The cost tools here use US industry-average pricing, but concrete and asphalt swing hard by region and fuel cost, so confirm with a local plant. Run the numbers first and you order once, pour once.