Concrete Calculator
Estimate the concrete volume for a rectangular project and see net volume, order quantity, metric volume and approximate bag counts.
Concrete to order
2.74 yd³
2.47 yd³ net · 66.67 ft³
Metric volume
2.10 m³
Approximate retail bags: 125 × 80 lb or 165 × 60 lb
Results are planning estimates. Check supplier product yields, densities and project specifications before ordering.
Concrete calculator guide
Use this estimator for rectangular slabs, pads, footings and similar projects. It converts the dimensions to cubic feet, then to cubic yards and cubic meters, and applies an ordering allowance.
Worked example
20 × 10 ft slab at 4 inches
Net volume = 20 × 10 × 4 ÷ 12 = 66.67 ft³ = 2.47 yd³. With a 10% allowance, the planning order quantity is about 2.74 yd³.
Important assumptions
- The calculator assumes a rectangular volume.
- Bag counts use approximate retail yields and are not a substitute for the manufacturer's stated yield.
- Structural concrete must follow the project drawings, approved mix design and local requirements.
FAQ
How much concrete should I order?
Calculate the net volume first, then add an allowance appropriate to the site and supplier. Confirm the final quantity with the ready-mix supplier.
Can this calculate a footing or irregular shape?
Yes for rectangular sections. Split irregular projects into simple rectangular sections and add their volumes.