How do I convert concrete cubic feet to cubic yards?

Divide cubic feet by 27. One cubic yard of concrete equals 27 cubic feet.

How many bags of concrete are in a cubic yard?

It depends on the bag size and mix yield. A cubic yard is about 45 80 lb bags if each bag yields about 0.60 cubic feet, or about 60 60 lb bags if each yields about 0.45 cubic feet.

Concrete estimate before you order

How much concrete do I need?

Enter dimensions for a slab, driveway, footing, or fence post holes. Get cubic feet, cubic yards, cubic meters, bag counts, cost, and a practical order note.

Example: 12 ft x 20 ft patio, 4 in thick, 10% waste About 3.26 yd3 to order, or about 147 80 lb bags.

Project type

Measure the pour

Price per yd3

Length (ft) Width (ft) Thickness (in) Sections

Diameter (in) Depth (ft) Number of holes Post/tube note

Total length (ft) Width (in) Depth (in) Run type

Step width (ft) Tread run (ft) Rise (in) Number of steps

Waste buffer (%) Ready-mix delivery fee

Bag yield assumptions

Bag yields vary by brand, mix, water ratio, and compaction. Edit these if your bag label lists a different yield.

40 lb ft3 60 lb ft3 80 lb ft3 90 lb ft3

Concrete yardage basics

Convert length, width, and depth into cubic yards and a supplier-friendly order amount.

Slabs and patios

Choose slab thickness for patios, sidewalks, shed pads, and garage floors.

Bag count guide

Compare 40, 60, 80, and 90 lb bag counts and see when bagging gets impractical.

Driveway concrete

Plan driveway yardage with thickness, multiple sections, and waste buffer notes.

Fence post holes

Estimate round post-hole volume by diameter, depth, and number of holes.

Waste buffer guide

Pick a 5%, 10%, or 15% buffer based on forms, excavation, and site conditions.

When to order ready-mix

Bagged concrete is handy for post holes, patching, and very small pads. Once an estimate climbs above roughly one cubic yard, the bag count, mixing time, and water consistency usually make a ready-mix truck worth pricing.

Planning note

This calculator is a planning estimate. Actual concrete needs vary with excavation accuracy, sub-base preparation, reinforcement, compaction, formwork, waste, and supplier minimums.