Concrete Calculator
Calculate concrete volume for slabs, columns, and steps in cubic yards, cubic meters, and number of bags.
Bags of 60 lb Concrete Needed
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Cubic Yards
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Cubic Meters
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What is Concrete Calculator?
The Concrete Calculator estimates the volume of concrete needed for slabs, columns, and steps. It converts your dimensions into cubic yards and cubic meters, and tells you how many 60 lb bags of pre-mixed concrete to purchase.
How to use
- 1 Select the shape: Slab, Column, or Steps.
- 2 Enter the dimensions for your chosen shape (length, width, thickness for slabs; radius and height for columns; rise, run, width, and step count for stairs).
- 3 Click Calculate to get the volume.
- 4 The result shows cubic yards, cubic meters, and the number of 60 lb bags needed.
- 5 Add 5–10% extra to your bag count to account for waste and spillage.
Formula
Example calculation
A slab 10 ft × 10 ft × 4 inches thick = 10 × 10 × 0.333 = 33.3 cu ft = 1.23 cu yd = 0.94 m³ ≈ 74 bags of 60 lb concrete.
Frequently asked questions
How many cubic feet does a 60 lb bag fill?
One 60 lb bag of pre-mixed concrete fills approximately 0.45 cubic feet when mixed.
Should I order extra concrete?
Yes — order 5–10% more than calculated to account for waste, spillage, and variations in your forms.
When should I use ready-mix instead of bags?
For projects over 1 cubic yard it is usually more economical to order ready-mix concrete from a supplier.
What is the difference between cubic yards and cubic meters?
1 cubic yard = 0.7646 cubic meters. The calculator shows both so you can order in whichever unit your supplier uses.
How thick should a concrete slab be?
Residential driveways typically need 4 inches, sidewalks 3–4 inches, and structural slabs 6 inches or more depending on load.