Concrete Bag Calculator
Volume, bag count, and rough cost.
Concrete Bag Calculator
Estimate concrete volume and bag quantities for slabs, trenches, post holes, and round piers. Enter the bag size you plan to buy, such as a 20 kg bag, and the calculator estimates the bag count.
Concrete Inputs
Slab and trench modes use length x width x depth. Post-hole and round-pier modes use diameter x depth x count. Bag counts are estimates based on a standard premix yield, then rounded up to a whole bag.
Concrete calculator FAQ
What if my bag has a different yield?
This calculator estimates standard premix yield from bag size. Check the product label before ordering if the bag lists a different yield or the job is structural.
Why does the result show both volume and bags?
The raw concrete volume helps you sense-check the result before relying on the rounded bag purchase recommendation.