Concrete Bag Calculator
Enter the volume you need and the bag size you're buying. The calculator returns the bag count plus how many pallets that is, with an optional waste allowance.
Your measurements
Bigger bags yield more concrete each (40 lb ≈ 0.30 ft³ up to 80 lb ≈ 0.60 ft³), so you need fewer — but an 80 lb bag is heavy to carry and mix.
Coverage
- Volume
- 9 ft³
80 lb bags needed
15 bags
What to buy
- Bag yield
- 0.6 ft³/bag
- Pallets
- 0.4 pallets(42/pallet)
Estimates only. Verify against your supplier's coverage figures before ordering.
The formula
Bags = Cubic feet ÷ bag yield (yields: 40 lb 0.30, 50 lb 0.375, 60 lb 0.45, 80 lb 0.60 ft³)
Example: For 9 ft³ using 80 lb bags: 9 ÷ 0.6 = 15 bags. Pallets usually hold 42 × 80 lb bags.
How it works
- 1Each bag yields a fixed volume of mixed concrete: 0.30 ft³ (40 lb), 0.375 ft³ (50 lb), 0.45 ft³ (60 lb), or 0.60 ft³ (80 lb).
- 2Divide the volume you need by the bag yield to get the bag count.
- 3Round up — you can't buy a partial bag — and add an optional waste allowance.
Frequently asked questions
How many bags of concrete are on a pallet?
A pallet typically holds 42 × 80 lb bags, 56 × 60 lb bags, or 80 × 40 lb bags, though this varies slightly by brand.
How many bags of concrete make a cubic yard?
A cubic yard is 27 cubic feet. That takes 45 of the 80 lb bags, 60 of the 60 lb bags, 72 of the 50 lb bags or 90 of the 40 lb bags.
How many bags of concrete do I need for a 10 × 10 slab?
A 10 ft × 10 ft slab poured 4 inches thick is 33.3 cubic feet. That is 56 of the 80 lb bags or 75 of the 60 lb bags, before any extra for waste.
How many bags of concrete do I need per fence post?
A typical 4 × 4 post set in a 10 inch wide, 30 inch deep hole needs about 1.15 cubic feet of concrete, which is two 80 lb bags. Wider or deeper holes need more, so work out the hole's volume in cubic feet and enter it above.