Concrete Weight Calculator

Knowing how much your concrete pour will weigh — and how much material to order — prevents costly under-ordering and structural surprises. Select your structure type (slab, footing, round footing, circular tube, or stairs), enter your dimensions, choose your concrete density, and set a waste factor to get the Total Weight in pounds. Secondary outputs include volume in cubic feet and cubic yards, plus the number of 60-lb and 80-lb bags needed for your project.

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Account for waste and spillage

Results

Total Weight

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Volume

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Volume

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60-lb Bags Needed

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80-lb Bags Needed

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Frequently Asked Questions

How much does concrete weigh per cubic foot?

Standard concrete typically weighs 150 pounds per cubic foot. Lightweight concrete weighs around 145 lbs/ft³, while heavy-weight concrete can weigh up to 160 lbs/ft³.

How do I calculate concrete volume for a slab?

Multiply length × width × thickness. Convert thickness from inches to feet by dividing by 12. For example, a 10×10 ft slab that's 4 inches thick = 10 × 10 × (4/12) = 33.33 cubic feet.

Why should I add a waste factor?

Adding 5-15% waste factor accounts for spillage, over-excavation, and irregularities in the subgrade. This ensures you have enough concrete to complete your project.

How many bags of concrete do I need?

A 60-lb bag yields about 0.45 cubic feet, while an 80-lb bag yields about 0.6 cubic feet. Divide your total volume by the yield per bag to determine how many bags you need.

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

There are 27 cubic feet in 1 cubic yard. Concrete is often sold by the cubic yard for large projects, while bags are measured in cubic feet coverage.

How do I calculate concrete for round footings?

Use the formula π × radius² × depth. For a 3-foot diameter footing that's 2 feet deep: 3.14159 × (1.5)² × 2 = 14.14 cubic feet.

Should I order extra concrete?

Yes, it's recommended to order 5-10% more than calculated to account for waste, spillage, and minor measurement variations. Running short during a pour can be costly and affect quality.