Bagged concrete and ready-mix delivery are two ways to buy the same material, and choosing between them is mostly a question of volume and labor. Estimate both and the right choice is usually obvious.
The short version
| Bagged concrete | Ready-mix delivery | |
|---|---|---|
| Best for | Footings, posts, small repairs | Slabs, walkways, patios |
| Practical ceiling | Roughly up to ~0.5–1 cu yd, before hand-mixing dozens of bags loses its appeal | Anything larger; plants may impose minimum orders |
| Sold by | Yield per bag (cu ft in the US) | Cubic yard (or cubic metre) |
| Watch out for | Yields differ by bag weight and brand | Short-load fees on small orders; the truck needs access |
The two options are alternatives — estimate both for comparison, but never order "37 bags plus 0.81 yards".
How to estimate bagged concrete
Every bag prints the volume of mixed concrete it yields — roughly 0.45 cu ft for a 60-lb bag and about 0.6 cu ft for an 80-lb bag, but check the bag you are actually buying, because products differ. The estimate:
For the slab from How to Calculate Concrete Volume — 22 cu ft required with a 10% allowance — a 0.6 cu ft bag gives 22 ÷ 0.6 = 36.7, so 37 bags. The Concrete Calculator labels this "Option A" and keeps its cost separate from ready-mix.
Two things make bagged estimates go wrong: using a yield from a different bag weight, and forgetting that the round-up is to whole bags. A generic "about half a cubic foot" guess drifts badly across a 37-bag order.
How to estimate ready-mix
Ready-mix plants sell wet concrete by the cubic yard (US) or cubic metre (elsewhere). The estimate is simply:
At 0.81 cu yd and a sample $155 per yard, the same pour costs about $126 — "Option B" in the calculator. Before you order, ask your local plant about:
- Minimum or short-load charges — orders below a threshold often carry a fee that changes the comparison
- Truck access — can the truck reach the pour, or does the last stretch move by wheelbarrow?
- Time on site — unloading time is usually included; long pour windows may not be
The crossover, in bags
Where do bags stop making sense? One cubic yard is 27 cu ft. At 0.6 cu ft per 80-lb bag that is 45 bags; at 0.45 cu ft per 60-lb bag, 60 bags. Mixing 45–60 bags by hand in one session — each requiring water, mixing, and placing before the concrete sets — is where most DIYers cross over to a truck. Half a cubic yard (roughly 23–30 bags) is the usual gray zone: feasible for a crew, miserable alone.
Cost factors that move the comparison
- Bag price vs yard price at your local suppliers — enter both into the calculator and compare Option A against Option B directly.
- Labor. Bags are cheap per bag and expensive per hour; the truck is the reverse.
- Short-load fees on small ready-mix orders, which can flip the comparison on modest pours.
- Waste tolerance. A truck pour with no slack risks a short pour; bags let you mix one more batch, which is why the waste allowance is still applied to both options.
Common mistakes
- Adding bagged and ready-mix results together when they were meant to be compared.
- Trusting a generic yield. The bag's printed yield is the only correct divisor.
- Comparing bag price to yard price without converting units. $6.50 per 0.6 cu ft bag is about $10.83 per cu ft — while $155 per cubic yard is about $5.74 per cu ft. Units decide the comparison.
- Ignoring site access until the truck arrives.
FAQ
Can I use bags for the slab and ready-mix for a later pour?
Yes — each pour is estimated and ordered separately. Just never combine the two estimates for one pour: they are two prices for the same material.
What about mixing bags in a rented mixer?
A mixer changes the labor math, not the quantity math — the bag count and cost stay the same, and the crossover point shifts upward because machine mixing handles more bags per hour.
Does either option include reinforcement or finishing?
No. Rebar, mesh, forms, curing, and finishing tools are separate purchases and decisions in both routes, and anything structural requires a qualified professional.