For small jobs, bagged concrete is cheaper and easier. For anything around one cubic yard or more — roughly 40-plus bags — ready-mix delivery usually wins on both price per yard and labor. The dividing line is the volume of your pour, so the first thing to do is calculate it with the concrete calculator.
The break-even, in plain terms
There's no single magic number because bag prices and delivery fees vary by region, but the practical thresholds hold up almost everywhere:
- Under about ½ cubic yard: Use bags. Delivery minimums and short-load fees make ready-mix wildly expensive at this size. A handful of bags and a wheelbarrow is the right tool.
- ½ to 1 cubic yard: The gray zone. Bags are still manageable, but you're starting to do real labor. If you value your weekend, lean toward delivery.
- Above about 1 cubic yard (40+ bags): Order ready-mix. The per-yard cost typically drops below bagged concrete, and you skip the brutal work of mixing dozens of bags by hand.
Do the bag math first
Knowing your yardage lets you get your bag count close. Here's the conversion the calculator uses:
- An 80-lb bag yields 0.60 cubic feet of mixed concrete.
- A 60-lb bag yields 0.45 cubic feet.
- A 40-lb bag yields 0.30 cubic feet.
A cubic yard is 27 cubic feet, which works out to:
- 45 bags of 80-lb, or
- 60 bags of 60-lb, or
- 90 bags of 40-lb.
Stop and picture 45 eighty-pound bags. That's 3,600 pounds you have to lift, open, mix, and pour before the first batch starts to set. For a single yard, ready-mix arrives in one truck and pours in minutes.
The hidden costs on each side
The sticker price isn't the whole story. Bags carry real costs that don't show on the receipt:
- Your labor. Mixing by hand or even with a rented mixer is hours of heavy work for a large pour.
- Cold joints. If you mix and pour in batches that set at different times, you get weak seams between them. A single ready-mix pour is monolithic and stronger.
- Equipment. A mixer rental, a a concrete mixing tub, buckets, and a wheelbarrow add up.
Ready-mix has its own costs to watch:
- Delivery and minimum-load fees. Most suppliers charge a flat delivery fee plus a short-load surcharge under a certain volume (often 3 to 4 yards).
- The waiting clock. Drivers allow a set amount of free unloading time; go over and you pay by the minute. Have your forms, tools, and helpers ready before the truck arrives.
Always order a little extra
Whichever route you choose, buy 5 to 10 percent more than your calculated volume. Forms bulge, the base isn't perfectly level, and you'll lose a bit to spillage. Running short mid-pour is far worse than having a couple of leftover bags — a stalled pour creates the cold joints you were trying to avoid.
With ready-mix this is especially important, since you can't easily order a half-yard top-up once the truck has left. Round up.
The most expensive concrete is the batch you didn't order and now have to add on top of a half-set slab.
A quick worked example
Say you're pouring a 12-by-12 patio at 4 inches thick. That's 144 square feet × 0.33 cubic feet per square foot ≈ 48 cubic feet, or about 1.8 cubic yards.
- By bag: roughly 80 of the 80-lb bags — a genuinely punishing day of mixing.
- By truck: under 2 yards, ordered as 2 to keep a margin, delivered and poured in one shot.
This is a clear ready-mix job. Thickness drives the volume, so if you're not sure how thick to go, read how thick should a concrete slab be first — it changes the math entirely.
The practical wrap-up
Let volume decide. Small pours under half a yard belong to bags; jobs at a yard or more belong to ready-mix delivery. Estimate your yardage in the concrete calculator, add 5 to 10 percent, and count your bags or place your order from there. Then plan your finish — and your timeline — around concrete curing time. Measure twice. Buy once.