Concrete Calculator

Calculate concrete needed for slabs, patios, and driveways. Get cubic yards, number of bags, and cost estimates.

How to Calculate Concrete

Multiply length × width × depth (in feet) to get cubic feet, then divide by 27 for cubic yards. This calculator includes 10% extra for waste.

Calculate square footage for rooms and spaces. Get paint and flooring estimates.

Calculate how much paint you need for any room. Account for doors, windows, and multiple coats.

Calculate flooring needed for any room. Get boxes, cost estimates for laminate, hardwood, tile.

Calculate fence materials: posts, rails, pickets, and concrete. Estimate costs by fence style.

Calculate mulch, gravel, or stone needed. Get cubic yards, bags, and weight for landscaping.

Calculate percentages instantly. Find what percent of a number is, percentage increase/decrease, and more.

How thick should a concrete slab be?

4 inches for sidewalks and patios, 6 inches for driveways, 8+ inches for heavy vehicles or foundations.

How many bags of concrete for 1 cubic yard?

About 45 80-lb bags, 60 60-lb bags, or 90 40-lb bags equal one cubic yard.

When should I order ready-mix vs bags?

Use bags for under 1 cubic yard. Order ready-mix delivery for larger projects—it's faster and ensures consistent mixing.

How much does concrete cost?

Ready-mix concrete costs $100-150 per cubic yard delivered. Bags cost more per yard but work better for small projects.