How do I calculate concrete volume for a slab?

Multiply length × width × thickness. For a 10ft × 12ft slab that's 4 inches thick: 10 × 12 × 0.33 = 39.6 cubic feet (1.1 cubic yards). Always add 5-10% extra for waste and spillage.

What is the standard concrete mix ratio?

The most common mix ratio is 1:2:3 (cement:sand:aggregate by volume) for general construction. For heavy-duty applications, use 1:1.5:3. The calculator adjusts material quantities based on your chosen mix ratio and total volume.

How many bags of concrete do I need?

An 80 lb bag covers about 0.6 cubic feet. For 1 cubic yard (27 cubic feet), you need approximately 45 bags. The calculator automatically converts your volume to bag count based on the bag size you select.

Should I add extra concrete for waste?

Yes, always add 5-10% for forms, spillage, and uneven ground. For complex shapes or remote pours, add 10-15%. The calculator includes a wastage factor setting to account for this automatically.

How do I calculate concrete for a round column?

Use the formula V = πr²h (pi × radius squared × height). For a 12-inch diameter column that's 8 feet tall: π × 0.5² × 8 = 6.28 cubic feet. The calculator handles cylindrical shapes automatically.

What's the difference between cubic feet and cubic yards?

One cubic yard equals 27 cubic feet. Ready-mix concrete is typically ordered in cubic yards, while bag quantities are based on cubic feet. The calculator converts between units automatically.

Concrete Calculator

ACI 318ConstructionMaterials

ACI 318Construction

Concrete Calculator

Enter dimensions to calculate concrete volume and material quantities

Frequently Asked Questions

Common questions about this calculator

Concrete Calculator

Shape Selection

Dimensions

Mix & Options

Frequently Asked Questions

Concrete Calculator

Shape Selection

Dimensions

Mix & Options

Frequently Asked Questions

01How do I calculate concrete volume for a slab?

02What is the standard concrete mix ratio?

03How many bags of concrete do I need?

04Should I add extra concrete for waste?

05How do I calculate concrete for a round column?

06What's the difference between cubic feet and cubic yards?