Concrete Bag Calculator
Enter the slab or pad dimensions. Use Imperial or Metric mode, then adjust individual units if needed.
Last updated: May 2026
Buying and sizing notes
- For larger pours, ready-mix delivery may be more practical than mixing many bags by hand.
How to use this estimate
What this includes
- Slab volume from length, width, and thickness
- Waste allowance
- Bag yield / bag size assumptions
What it does not include
- Subgrade preparation
- Reinforcement
- Delivery minimums
- Local concrete requirements
Common mistakes
- Entering thickness in feet instead of inches
- Forgetting to round up bags
- Skipping extra material on small pours
Quick questions
Should I round up concrete bags?
Yes. Running short on concrete is usually worse than having an extra bag or two, especially on small projects.
Does this include waste?
Yes, if you leave a waste allowance entered. The default is meant as a planning buffer, not a guarantee.
Related calculators
Helpful tools for nearby decisions.