Concrete Volume & Cost Calculator
Estimate how much concrete you need for a slab, circular pad, or column. Add waste and optional cost per cubic yard to plan your order.
Tip: Most contractors add 5% to 12% for spillage, uneven subgrade, and over-excavation.
How this concrete calculator helps
Ordering too little concrete can stop your pour mid-project. Ordering too much can waste money. This calculator gives a fast estimate in cubic yards, cubic feet, and cubic meters so you can order confidently. It also adds a waste factor and gives a rough ready-mix cost estimate.
Concrete volume formulas used
1) Rectangular slab or footing
Volume = Length × Width × Depth
This is ideal for patios, driveways, sheds, and strip footings.
2) Circular slab
Volume = π × (Diameter ÷ 2)2 × Depth
Use this for round pads, hot tub bases, and tank pads.
3) Column or pier (cylinder)
Volume = π × (Diameter ÷ 2)2 × Height
Useful for deck footings, piers, and structural columns.
Measurement tips before you calculate
- Measure in one consistent unit (all feet or all meters).
- Use finished dimensions, not rough guesses.
- For variable depth pours, calculate each section separately and add them.
- Always include waste for real-world conditions.
Converting units quickly
- 1 cubic yard = 27 cubic feet
- 1 cubic meter = 35.3147 cubic feet
- 1 cubic yard ≈ 0.7646 cubic meters
Ready-mix suppliers often quote concrete by the cubic yard in the U.S., so that output is typically the most useful for ordering.
How much bagged concrete do you need?
The calculator also estimates bag counts using common yields:
- 80 lb bag ≈ 0.60 ft³
- 60 lb bag ≈ 0.45 ft³
- 50 lb bag ≈ 0.375 ft³
Bagged mix is practical for small jobs, but for larger pours, ready-mix delivery is usually faster and more consistent.
Common mistakes to avoid
- Forgetting to convert inches to feet (or centimeters to meters).
- Using nominal lumber dimensions instead of actual form dimensions.
- Skipping the waste factor.
- Not confirming minimum delivery volume with your local plant.
Final planning checklist
- Recheck dimensions and slope requirements.
- Confirm rebar, wire mesh, and base prep are complete.
- Schedule enough labor for placement and finishing.
- Have curing materials ready immediately after finishing.
A good estimate is the first step to a smooth pour. Use the calculator above, then verify with your supplier if your job has unusual geometry or structural requirements.