Every concrete project hits the same fork in the road: mix bags yourself or call a ready-mix truck? The answer isn’t a matter of preference — it’s arithmetic. Bags are cheap to start and expensive per yard; trucks are expensive to start and cheap per yard. Somewhere between them is a break-even point, and for most people it lands lower than they expect.
The cost per cubic yard, honestly compared
Bagged: An 80 lb bag yields about 0.60 ft³ of concrete, so a cubic yard (27 ft³) takes 45 bags. At $5–$8 per bag, that’s $225–$360 per yard in material — plus a mixer rental (~$60–$90/day) for anything beyond a few bags.
Ready-mix: Standard mix runs $120–$180 per yard delivered, but small orders trigger a short-load fee of $50–$150 plus a delivery surcharge. On a 1-yard order, real cost is often $250–$350; by 3 yards, the fees dilute to under $50 per yard.
| Volume | Bagged (80 lb, $6.50/bag) | Ready-mix ($150/yd³ + $100 fees) |
|---|---|---|
| 0.25 yd³ (12 bags) | ~$78 | ~$140 |
| 0.5 yd³ (23 bags) | ~$150 | ~$175 |
| 1 yd³ (45 bags) | ~$293 + mixer | ~$250 |
| 2 yd³ (90 bags) | ~$585 + mixer | ~$400 |
| 3 yd³ (135 bags) | ~$878 + mixer | ~$505 |
On material cost alone, the crossover sits around 0.75–1 cubic yard. Add labor and it moves lower still.
The labor you’re not pricing
Forty-five 80 lb bags is 3,600 lb of material per yard — lifted off a pallet, into a cart, into a mixer, and out again. A capable DIYer with a drum mixer produces about 15–20 bags per hour sustained. One yard is a hard 2.5–3 hour mixing session before any placing and finishing; two yards is a full day of grinding work with helpers.
There’s a quality cost too. A slab poured from 60 small batches over four hours has dozens of internal seams and inconsistent water content. Concrete stiffens noticeably in 45–60 minutes, so early batches are setting while you’re still mixing late ones — a real problem for any slab bigger than a few feet across that needs a uniform finish.
When bags are clearly right
- Under about 15–20 bags (~0.25 yd³): post footings, small pads, repairs, mailbox and mower strips.
- Inaccessible spots where a truck chute or pump can’t reach and wheelbarrowing ready-mix isn’t practical.
- Staged work — setting a dozen fence posts over several weekends can’t use a truck at all.
Count bags precisely with the bag calculator or the dedicated 80 lb bag calculator — and remember a 60 lb bag yields only ≈0.45 ft³, so smaller bags mean roughly a third more lifting per yard.
When the truck is clearly right
- Anything over ~1 yard, and arguably over half a yard if your time has value.
- Monolithic slabs — patios, driveways, garage floors — where one continuous pour gives a uniform, seam-free result.
- Specified strength. The plant batches by weight and can certify 3,000 or 4,000 psi; hand mixing can’t.
A 10 × 12 ft patio at 4 inches is 40 ft³ = 1.48 yd³ = 67 eighty-pound bags (5,300+ lb of material). That’s firmly truck territory even with the short-load fee.
The decision procedure
- Compute your volume with the concrete calculator or volume calculator.
- Under 0.25 yd³: buy bags, no debate.
- 0.25–0.75 yd³: bags if the site is awkward or the work is staged; otherwise get one ready-mix quote including fees — u-cart or a small-batch trailer service may also bridge this gap.
- Over 0.75–1 yd³: order the truck. Compare full costs in the cost calculator.
One warning either way
Whatever you choose, have the volume right before committing. Running out of bags mid-slab means a cold joint while you drive to the store; ordering a truck 20% short means a second delivery with full fees. Size the pour, add 5–10% waste, and round up — surplus concrete is an annoyance, but a shortfall is a defect you’ll look at for twenty years.