Quikrete Concrete Calculator
Calculate how many bags of Quikrete concrete mix you need — enter your slab dimensions to get the bag count for 40, 60 and 80 lb bags, with a waste allowance and an estimated cost.
United States — national average · 2026 prices
Material only unless stated as installed. Excludes tax, permits and local labour. Verify with local suppliers — see how we calculate.
How this calculator works
Every figure above comes from the formula below, applied to the assumptions listed. Nothing is looked up from a hidden table — you can reproduce the result by hand.
Formula
cubic feet = length × width × thickness (in) ÷ 12 × (1 + waste ÷ 100)
bags = cubic feet ÷ bag yield, rounded up
bag yield: 80 lb = 0.60 · 60 lb = 0.45 · 40 lb = 0.30 cu ft
Assumptions & limits
- Quikrete Concrete Mix is sold in 40, 60 and 80 lb bags, yielding about 0.30, 0.45 and 0.60 cu ft — so roughly 90, 60 or 45 bags per cubic yard. All three sizes are selectable above.
- Quikrete is the most widely stocked bagged-concrete brand in US home centres, so the 40 lb bag is a realistic option for small jobs where handling weight matters.
- Yields are for the general-purpose Concrete Mix. Quikrete's Fast-Setting and 5000 lines yield differently — read the printed yield on the bag you actually buy.
- Bag yields follow the QUIKRETE Concrete Mix data sheet. Other brands and mix types (fast-setting, high-early-strength) yield slightly differently — check your bag.
- Bag prices assume $6.00 per 80 lb, $4.75 per 60 lb and $3.75 per 40 lb bag.
- Default waste allowance is 10%, higher than the ready-mix default because part-bags and spillage cost proportionally more on small jobs.
- Counts are rounded up to whole bags — you cannot buy two thirds of a bag.
- For a post hole, the figure is the hole volume. Subtract the post itself for a closer number.
Worked example
An 8 ft × 8 ft shed pad, 4 inches thick, 10% waste, in Quikrete 80 lb bags
- Cubic feet = 8 × 8 × 4 ÷ 12 = 21.3, plus 10% waste = 23.5 cu ft
- 80 lb bags = 23.5 ÷ 0.60 = 39.1 → 40 bags
- 60 lb bags = 23.5 ÷ 0.45 = 52.1 → 53 bags
- Cross-check: 23.5 cu ft ÷ 27 = 0.87 yd³, and Quikrete lists ~45 × 80 lb bags per yd³
Result:40 × 80 lb bags of Quikrete mix. At this count, pricing a ready-mix short load is worth a phone call.
Built and maintained by Christoph Ballmer, Honeygoat GmbH
Method and constants last checked against the calculator code on August 17, 2026. Independent trade review is not yet in place for this calculator — see how we handle review.
Read the site-wide calculation methodology · estimate vs. quote and safety limits
How many bags of Quikrete concrete do I need?
Quikrete is the most widely stocked bagged concrete brand in the US. Its general-purpose Concrete Mix comes in 40, 60 and 80 lb bags, with standard yields of about 0.30, 0.45 and 0.60 cubic feet — so it takes roughly 90, 60 or 45 bags to make a cubic yard. This calculator sizes a Quikrete job from your slab, footing or post-hole dimensions.
To size it, the calculator takes your slab volume and divides by the bag yield, rounding up with a waste allowance. Quikrete concrete mix is sold in 40, 60 and 80 lb bags, and the result shows the count for each size so you can pick whichever your store stocks or you can lift.
bags = (length × width × thickness ÷ 12, in cu ft) ÷ bag yield
For a bigger pour, compare Quikrete bags against ready-mix with the concrete calculator, or price a delivery with the concrete cost calculator.
Concrete bag calculators by brand
Size a job with another concrete brand:
Frequently asked questions
How many bags of Quikrete concrete do I need?
Find your slab volume in cubic feet (length × width × thickness, all in feet), then divide by the bag yield: about 0.60 cu ft for an 80 lb bag, 0.45 for 60 lb and 0.30 for 40 lb. Quikrete concrete mix comes in 40, 60 and 80 lb bags. The calculator above does this from your dimensions and rounds up.
How many Quikrete bags make a cubic yard?
A cubic yard is 27 cubic feet, so it takes about 45 × 80 lb bags, 60 × 60 lb bags, or 90 × 40 lb bags of Quikrete concrete mix — the same as any general-purpose mix at standard yields.
Which Quikrete product should I use for fence posts?
Fast-Setting Concrete Mix, and it skips the mixing entirely: pour the dry mix into the hole around the post, add water on top, and it sets in 20–40 minutes. A 50 lb bag of Fast-Setting yields about 0.375 cu ft, so a typical post hole takes one to two bags. Enter the hole as a round column in the concrete calculator to size it exactly.
What is the difference between Quikrete Concrete Mix and Quikrete 5000?
Strength and cure speed. The standard Concrete Mix reaches about 4,000 PSI at 28 days and suits pads, footings and post setting. Quikrete 5000 reaches 5,000 PSI, gains strength faster and is walkable sooner — the choice for driveways, countertops and anything structural. Both come in the same bag sizes with similar yields.
How much water does an 80 lb bag of Quikrete take?
About 3 quarts per 80 lb bag, added gradually — the bag directions are the authority. Err on the dry side: a soupy mix is easier to pour but measurably weaker, and you can always add a little water while you can never take it out.
How many bags of concrete for a fence post?
For a typical 4-inch post in a 10-inch-wide hole 2 feet deep, plan on roughly one to two 50–60 lb bags per hole. Wider or deeper holes need more. Enter the hole as a round column above (diameter and depth) to size it exactly, and remember to subtract the post itself for a close figure.