Concrete Bag Calculator
Converts a concrete volume into a bag count for every common bag size, so you can compare what your merchant actually stocks. It also shows the total weight — the number that decides whether this is a bag job at all.
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
The formula
bags = volume ÷ yield per bag, rounded up
Bag yields are the mixed volume printed on the bag, not the dry powder volume. A 25 kg bag makes about 12.5 litres; an 80 lb bag about 0.6 ft³.
What to watch out for
Bag yields, mixed:
- 80 lb bag — 0.60 ft³ (17.0 L). About 45 to a cubic yard.
- 60 lb bag — 0.45 ft³ (12.7 L). About 60 to a cubic yard.
- 40 lb bag — 0.30 ft³ (8.5 L). About 90 to a cubic yard.
- 25 kg bag — 12.5 L. About 80 to a cubic metre.
- 20 kg bag — 10 L. About 100 to a cubic metre.
The weight figure matters more than the count. A cubic metre is two tonnes of bags — that is a pallet, a delivery, and a day of mixing before you have poured anything.
Frequently Asked Questions
How many bags of concrete in a cubic yard?
About 45 × 80 lb bags, 60 × 60 lb bags, or 90 × 40 lb bags. In metric, roughly 80 × 25 kg bags to a cubic metre.
How many 25 kg bags make a cubic metre?
80 bags, since each yields about 12.5 litres mixed. That is two tonnes of material.
At what point should I stop using bags?
Around 0.5 m³ (0.65 yd³). Beyond that you are mixing over a tonne by hand, and a continuous pour becomes hard to achieve — which is where cold joints and weak planes come from.
Does the bag yield change with the mix?
Slightly. General-purpose, ballast and postcrete all differ a little, and the figure on the bag assumes the stated water ratio. Treat these yields as accurate to within a few percent.