Ready-Mix vs Bagged Concrete: Which Should You Order?

Length × width × thickness in consistent units gives cubic feet or cubic metres. Divide cubic feet by 27 for cubic yards. A 10 × 10 ft slab at 4 inches is about 3.1 yd³ before waste. A single fence-post hole is often 0.05–0.1 yd³. Those two jobs do not belong on the same order ticket.

Run the numbers in the Concrete Calculator before you phone a plant or fill a trolley. Add a small waste allowance for uneven subgrade and spillage — often 5–10% on a simple pad, more if the dig is rough. Guessing “a couple of bags” on a patio is how weekends turn into emergency second trips.

If you also need a gravel sub-base, keep that takeoff on the Gravel Calculator. Sub-base volume is not concrete volume.

As a planning rule of thumb, bagged concrete starts to lose the argument somewhere around one cubic yard — roughly 40–45 of the common 80 lb bags, depending on mix and yield. Below that, bags often win on flexibility. Above that, a truck usually wins on labour even if the plant’s per-yard price looks steep.

Check yield on the bag, not a memory of “two square feet per bag.” Enter bag size and project volume in the Concrete Bag Calculator so the bag count matches the slab or footing you measured. Rounding up to whole bags is normal; rounding down is how you run dry with wet forms waiting.

One yard is not a hard law. With helpers, a mixer, and a short carry, you might push past a yard in bags. Alone on a hot day with a long barrow run, half a yard of bags can already feel like a bad decision.

Each bag means cut, dump, mix, place, and rinse tools. Even with a powered mixer, a yard of bags is a long morning. Ready-mix arrives as a continuous stream if access is good — chute or pump — and the clock starts when the drum is spinning, not when you open the first bag.

Price the hour, not only the material. If four people spend half a day mixing bags for a slab you could have placed in an hour from a truck, you did not save money — you spent a Saturday. The Concrete Cost Calculator helps you compare material lines; add labour and hire (mixer, wheelbarrow, pump) so the bag aisle does not look artificially cheap.

Bags let you pace the day in small batches. A truck wants a crew ready when it arrives. Match the method to the crew you actually have.

Ready-mix plants often charge a short-load or minimum fee when the order is small. A “cheap” half-yard on the phone can bill closer to a full small load once fees, environmental charges, and waiting time land on the ticket. Ask for the all-in delivered price before you commit.

Access matters as much as volume. Tight side yards, soft lawns, low trees, and weight limits push you toward bags even when volume says truck. No chute access means a pump quote — another line that can flip the comparison.

If forms are not ready when the truck arrives, demurrage clocks tick. Bags forgive a slow morning. Trucks do not. Make pour day placement day, not carpentry day.

Bagged mixes from one brand and batch are usually close enough for a grey pad. Stretch a large slab across many bags mixed over hours and you can get shade bands where water content drifted. Ready-mix from one load is more even for visible slabs and garage floors.

If you must use bags on a visible pour, buy one lot, keep water measured, and mix to the same slump every batch. Do not “eyeball a splash” from bag to bag. That is how a patio looks pieced together under afternoon light.

Fence posts, mailbox footings, and deck pier holes are bag territory for most homeowners. You dig a few holes, mix as you go, and you are not fighting a short-load fee for a wheelbarrow of mud. Fast-setting bag mixes exist for posts — read the bag; some are not meant for structural slabs.

Sonotube piers can go either way. A handful of tubes: bags. A whole deck of piers the same afternoon with a crew: maybe a small ready-mix order if access is easy and the plant’s minimum does not punish you. Run total volume first, then count how many separate places the concrete has to land.

Do not order a truck for six post holes because a neighbour said ready-mix is “always better.” Continuous slabs, yes. Scattered weekend holes, bags.

Patios, garage slabs, sidewalks, and driveway sections want a continuous pour when possible. Cold joints and mismatched batches show forever. That is where ready-mix earns its keep — one load, one placement, one finish pass while the surface is still workable.

Thickness drives volume hard. Moving from 3.5 to 4 inches on a big slab is not a rounding error. Confirm thickness, then lock it in the Concrete Calculator before you compare bag counts to truck yards.

Reinforcement, vapour barriers, and control joints are part of the slab. Bags vs truck only answers how the concrete arrives — not whether the detail is right.

Under roughly 0.5 yd³ with easy mixing: bags, almost always. Around 0.5–1 yd³: compare bag count (Concrete Bag Calculator), all-in truck price with short-load fees, crew size, and carry distance. Over about 1–1.5 yd³ with decent access: call ready-mix unless the site cannot take a truck.

Price materials with the Concrete Cost Calculator using local bag and per-yard rates, then add mixer hire, delivery fees, and your time. Put a ready-mix quote with fees beside the bag tally on one scrap of paper — the answer is usually obvious.