Enter your slab, footing or post dimensions and pick your Quikrete bag size - 40, 60 or 80 lb - to get the exact number of bags to buy. Works for slabs, footings, columns and fence posts.
Net volume
50.0 cu ft
The calculator works out the volume of your pour, adds a wastage allowance, then divides by the yield of one Quikrete bag to give the number of bags:
bags = ceil( volume × wastage ÷ bag yield )
Quikrete prints the yield on every bag - 0.30 cu ft for 40 lb, 0.45 cu ft for 60 lb, 0.60 cu ft for 80 lb - and those exact yields are the bag options above. Pouring more than one element (a slab plus a few footings)? Add a section for each and the bags round once for the whole order. All math runs in exact metric internally, so switching between feet and metres never changes the answer.
| Bag | Yield (set concrete) | Bags per cubic yard |
|---|---|---|
| 40 lb | 0.30 cu ft | ~90 |
| 60 lb | 0.45 cu ft | ~60 |
| 80 lb | 0.60 cu ft | ~45 |
A 10 ft × 10 ft slab at 4 inches thick, using 80 lb bags:
It depends on the volume and the bag size. One 80 lb bag of Quikrete yields about 0.60 cubic feet, so a cubic yard (27 cu ft) takes about 45 bags. A 60 lb bag yields 0.45 cu ft (about 60 bags per yard) and a 40 lb bag yields 0.30 cu ft (about 90 bags per yard). Enter your slab or footing size above and pick the bag - the calculator returns the exact count.
An 80 lb bag of Quikrete Concrete Mix makes about 0.60 cubic feet of set concrete - enough for a 2 ft × 2 ft pad at about 1.75 inches thick, or roughly an 18-inch square at 3 inches. The 60 lb bag makes 0.45 cu ft and the 40 lb bag 0.30 cu ft. These yields are built into the bag options in the calculator.
For a typical 4×4 post in a 10-inch-wide hole dug 2 feet deep, you need roughly one to two 50 lb bags of Quikrete Fast-Setting Mix per hole. Set the calculator shape to "Circle / column", enter the hole diameter and depth, and it gives the volume and bag count - remember the post itself displaces some concrete, so round down slightly.
Bagged Quikrete suits small jobs - posts, small pads, repairs - and lets you mix only what you need. Once a job needs roughly a cubic yard (around 45–90 bags depending on size), ordering ready-mix delivered by the truck is usually cheaper and far less work than mixing dozens of bags. The calculator shows both the bag count and the bulk volume so you can compare.
Use standard Quikrete Concrete Mix for slabs, footings and general work; Quikrete Fast-Setting Concrete Mix for fence posts and where you want it to set quickly (often without pre-mixing); and Crack-Resistant or 5000 mixes for higher-strength or thinner pours. The bag yields are similar, so the calculator's bag count applies across the mixes - check the exact yield on your bag.
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