Concrete cubic yards to bags

Concrete is sold by volume. Bagged premix is sold by weight. The bridge between them is the per-bag yield — and it changes with the mix, not just the bag. Enter a volume, get the bag count for every size.

01 How the math works

One cubic yard is 27 cubic feet. Every bag of premix lists a yield — the placed volume one bag makes. Divide the volume by that yield and you have the bag count. That is the whole conversion.

The yield is the number that matters, and it is set by the product. Standard concrete mix yields 0.60 ft³ per 80 lb bag, 0.45 ft³ per 60 lb, and 0.30 ft³ per 40 lb (Quikrete data sheet 1101). Fast-setting post mix yields 0.375 ft³ per 50 lb bag (Quikrete 1004) — a different bag, a different yield, a different bags-per-yard count.

02 Worked example

Take exactly one cubic yard (0.76 m³) of standard mix, ordered in 80 lb bags.

That is 27 ft³. At the 0.60 ft³ yield, the clean conversion is 45 bags (27 ÷ 0.60). Add a 10% waste factor and it rounds up to 50 bags — 4,000 lb (1,814 kg) of dry mix to haul, open, and combine. In 60 lb bags the same yard is 60 bags before waste; in 40 lb bags it is 90. The concrete is identical; only the number of trips to the truck changes.

03 When this calculator is wrong

The count above is the arithmetic. Two things move it in the real world, and one thing tells you to stop converting altogether.

• The yield belongs to the mix, not the weight. A generic "cubic yards to bags" table keyed only to bag weight breaks the moment the product changes. Fast-setting post mix is a 50 lb bag that yields 0.375 ft³, so a yard is 72 bags — not whatever a 50 lb line in a standard-mix table would say. Countertop and high-strength mixes have their own yields too. Read the bag before you trust a per-yard number.
• The listed yield is a ceiling. The 0.60 ft³ figure assumes the manufacturer's water ratio. Add water past that and each bag yields less, so the honest move is to treat the computed count as the floor and round up — which is what the waste factor is doing here.
• Above one yard, bags stop making sense. A cubic yard is 45 eighty-pound bags — 3,600 lb of dry mix — to lift and mix by hand inside concrete's working time. Beyond that, ready-mix wins on cost per yard, on uniformity, and on time. Most US suppliers charge a short-load fee of $50–150 for orders under 2 yd³, typically recovered before you have finished mixing the second bag. The exception is access: if the truck can't reach the form — a remote backyard, a basement, a second-story deck — bagged or pumped is the only option regardless of volume.

04 What to do with the result

If your volume is under 1 yd³ (0.76 m³), buy the bag count above and go. Order the rounded-up number, never the raw one — concrete can't be topped up mid-pour, and finishing a slab short is the kind of mistake you make once. For small residential work under 2 yd³, bump the waste factor to 15%: small batches lose more to the mixer, the wheelbarrow, and the chute than a production pour does.

If the number of bags is climbing past 45–50, price a short load of ready-mix before you load the cart. One yard delivered weighs about 3,915 lb (1,776 kg) and arrives mixed. The same yard in bags is the same weight, in 40-to-90 pieces, mixed by you.

05 Common questions

How many 80 lb bags of concrete are in a cubic yard?

At the standard 0.60 ft³ yield per 80 lb bag, one cubic yard is 45 bags (27 ft³ ÷ 0.60). With a 10% waste factor, order 50 bags — about 4,000 lb of dry mix.

How many 60 lb bags are in a cubic yard?

60 bags. A 60 lb bag yields 0.45 ft³, and 27 ÷ 0.45 = 60 exactly.

How many 40 lb bags are in a cubic yard?

90 bags. A 40 lb bag yields 0.30 ft³, and 27 ÷ 0.30 = 90. The small bags mean the most lifting for the same yard of concrete.

Does fast-setting mix use the same bag count?

No. Fast-setting post mix comes in 50 lb bags that yield 0.375 ft³, so a cubic yard is 72 bags (27 ÷ 0.375). The per-yard count follows the mix's yield, not the bag weight — switch the mix toggle above to see it.

Is it cheaper to buy bags or ready-mix for a full yard?

For a full yard, ready-mix. Bags stop being sensible around 45–60 of them: that's 3,600–4,000 lb to mix by hand in roughly 90 minutes of working time. The short-load fee for a small ready-mix delivery — typically $50–150 — is usually less than the cost and effort of the bags, unless the truck physically can't reach the pour.