Concrete Calculator

Calculate cubic yards of concrete for slabs, footings, columns, and steps. Get exact bag counts for smaller jobs.

Results are estimates only — actual material needs vary by site conditions, waste, and product specifications. Always verify quantities with a qualified contractor before purchasing. HandymanCalc is not liable for material shortfalls or overages.

Shape
Slab Dimensions
ft
ft
in
Waste
FAQ

Frequently Asked Questions

3 questions
Q1 How many bags of concrete make a cubic yard?
It takes approximately 45 bags of 80 lb concrete, or 60 bags of 60 lb concrete to make one cubic yard.
Q2 How thick should a concrete slab be?
Standard residential slabs are 4 inches thick. Driveways should be 4–6 inches. Heavy vehicle areas should be 6 inches or more.
Q3 What is the formula for a concrete slab?
Length (ft) × Width (ft) × Thickness (in ÷ 12) ÷ 27 = cubic yards. Always add 5–10% for waste and spillage.