Concrete Calculator
Estimate concrete volume for a rectangular slab, square footing, round column, round slab, wall or stairs in metric or feet — with bag counts, waste and ready-mix cost.
Runs 100% in your browser — nothing is uploaded.
What are you trying to calculate?
You need
2.04
yd³
- Calculated
- 1.85 yd³
- With 10% waste
- 2.04 yd³
- Cubic feet
- 50.0 ft³
- Cubic meters
- 1.42 m³
- 40-lb bags
- 184 × 40-lb bags
- 60-lb bags
- 123 × 60-lb bags
- 80-lb bags
- 92 × 80-lb bags
Assumptions
27 ft³ = 1 yd³ · bags: 0.3 / 0.45 / 0.6 ft³ per 40 / 60 / 80-lb bag · waste applies to the whole order.
Formula
Volume = area × thickness; πr²h for columns; π(R² − r²)h for round slabs; steps ≈ width × (rise × run ÷ 2) × risers. 27 cu ft = 1 yd³ = 0.7646 m³.
About this calculator
Estimates are for planning. Add waste for spillage and uneven forms; ready-mix trucks usually deliver in whole or half-yard increments.
How to use
- 1
Choose the structure type.
- 2
Pick feet or meters and enter dimensions (and an optional ready-mix price).
- 3
Read volume, bags and cost — add waste to the order.
Frequently asked questions
How much does one 80-lb bag make?
Roughly 0.6 cubic feet (about 0.022 yd³). 40- and 60-lb bags make about 0.3 and 0.45 cu ft.
Should I order extra?
Yes — 10% waste is typical for slabs and pours into uneven forms.
Do stairs need a platform?
Often. This estimate covers the tread steps only; add any landing as a small slab.
Please note: Results are estimates for general information only and are not professional or medical/financial advice.