How many bags of concrete do I need for a 10x10 slab?

For a standard 10x10 ft slab with 4-inch thickness, you'll need approximately 1.23 cubic yards or 45 bags of 60lb concrete (1 cubic foot per bag).

How do I convert cubic yards to cubic feet?

Multiply cubic yards by 27 to get cubic feet. For example, 2 cubic yards = 54 cubic feet.

What's the difference between 60lb and 80lb concrete bags?

A 60lb bag yields about 0.45 cubic feet, while an 80lb bag yields about 0.60 cubic feet. 80lb bags are more efficient but heavier to work with.

Concrete Quantity Calculator

Quantity result	Estimate	How to use it
Cubic feet	0.00 ft³	Useful for bagged concrete and small pours.
Cubic yards	0.00 yd³	Ready-mix suppliers quote concrete by cubic yard.
60 lb bags	0	Rounded up using about 0.45 cubic feet per bag.
80 lb bags	0	Rounded up using about 0.60 cubic feet per bag.

Quantity result

Estimate

How to use it

Cubic feet

0.00 ft³

Useful for bagged concrete and small pours.

Cubic yards

0.00 yd³

Ready-mix suppliers quote concrete by cubic yard.

60 lb bags

Rounded up using about 0.45 cubic feet per bag.

80 lb bags

Rounded up using about 0.60 cubic feet per bag.

How to Calculate Concrete Quantity

Calculating the correct amount of concrete is crucial for any construction project. Whether you're pouring a slab, setting post footings, or building a retaining wall, accuracy prevents expensive waste or stressful shortages.

The Basic Formula

Concrete is measured in volume (cubic feet or cubic yards). The basic formula for a rectangular slab is:

Length (ft) × Width (ft) × Thickness (ft) = Volume in Cubic Feet

Why Cubic Yards?

Most ready-mix suppliers sell concrete by the cubic yard. One cubic yard equals 27 cubic feet. To convert your result, simply divide cubic feet by 27.

Bagged Concrete vs. Ready-Mix

For smaller projects (under 1 cubic yard), using pre-mixed bags is often easier. Our calculator estimates the number of bags you'll need based on standard sizes:

60lb Bag: Yields approximately 0.45 cubic feet
80lb Bag: Yields approximately 0.60 cubic feet

Tips for Success

Prepare the Subgrade: Ensure your base is compacted and level to avoid cracking.
Account for Waste: We recommend adding 5-10% to your total to account for uneven ground and spillage.
Safety First: Wet concrete is caustic. Always wear gloves, long sleeves, and eye protection.

Frequently Asked Questions

How do I calculate concrete quantity for a slab?

For a rectangular slab, multiply length by width by thickness in feet to get cubic feet, then divide by 27 to convert to cubic yards.

How many concrete bags do I need?

Divide the required cubic feet by the bag yield. This calculator uses about 0.45 cubic feet for a 60 lb bag and about 0.60 cubic feet for an 80 lb bag, then rounds up.

Should I order extra concrete?

Yes. Add 5% to 10% for uneven ground, spillage, and small measuring errors. Running short during a pour is usually more expensive than having a small amount extra.

Concrete Quantity Calculator

Dimensions

Concrete Needed

Bags Needed