How Many Bags of Concrete Do I Need? Bag Calculator

How Many Bags of Concrete Do I Need?

Enter your project and get the number of bags for every common bag size, using the yield printed by the manufacturer. Pick a bag size to price it.

Bag yields

Yields from the QUIKRETE Concrete Mix data sheet
Bag	ft³ per bag	yd³ per bag	Bags per yd³	Sq ft at 4 in
40 lb	0.300	0.0111	90	0.90
50 lb	0.375	0.0139	72	1.13
60 lb	0.450	0.0167	60	1.35
80 lb	0.600	0.0222	45	1.80

Other brands publish similar yields for standard concrete mix, but always check the bag: high-strength, fast-setting and fiber mixes can differ. In metric, the calculator uses 0.008 m³ per 20-kg bag and 0.010 m³ per 25-kg bag from Hanson's data sheet; some brands list more (see methodology).

Which bag size should I buy?

80 lb: fewest bags and trips to the mixer, and usually the lowest cost per cubic foot. Heavy to carry.
60 lb: easier to lift and pour by hand; you need a third more bags than with 80 lb.
40 or 50 lb: handy for a post or two, repairs, or where you have to carry bags a distance.

Compare prices per cubic foot, not per bag: divide the bag price by its yield. Enter your local price in the calculator to see the total for the bag size you pick.

Bags vs a truck

Each cubic yard is 45 bags of 80-lb mix, or 3,600 lb of bags to haul and mix. Past a yard or so, ready-mix is often less work; see ready-mix vs bags.

Frequently asked questions

How many bags of concrete are in a yard?

Using QUIKRETE’s published yields: 45 bags of 80 lb, 60 bags of 60 lb, 72 bags of 50 lb or 90 bags of 40 lb make one cubic yard.

How many cubic feet is an 80-lb bag of concrete?

About 0.60 ft³. A 60-lb bag makes 0.45 ft³, a 50-lb bag 0.375 ft³ and a 40-lb bag 0.30 ft³.

How many bags of concrete for a 10x10 slab?

At 4 inches thick with 10% extra, a 10 × 10 ft slab needs 62 bags of 80-lb mix or 82 bags of 60-lb mix.

Should I round up the number of bags?

Yes, always round up, and keep the waste allowance. Unopened bags can usually be returned or saved for another job; running out mid-pour leaves a weak joint.