How Many Concrete Truck Loads Do I Need? A UK Guide

A standard ready-mix truck in the UK, the six-wheel drum mixer you see on the road, has a maximum legal payload of around 6 m³ of concrete. The drum itself is physically bigger, but the weight of a full 6 m³ is roughly what puts the truck at its legal axle limit, so 6 m³ is the practical ceiling for a standard rigid mixer. Larger 8-wheel trucks can carry closer to 8 m³, but they're heavier, need better access, and not every depot runs them.

Concrete weighs about 2.4 tonnes per cubic metre, so 6 m³ is roughly 14.4 tonnes of concrete sitting on top of a truck that already weighs a good deal on its own. That weight is the reason for the limit, and the reason a fully loaded mixer needs a firm, level surface to stand on and won't happily drive across a soft lawn to reach the back garden.

Takeaway: plan around 6 m³ per standard mixer as the working figure, and only assume 8 m³ if the supplier has confirmed a larger truck can actually reach your site.

Suppliers split concrete delivery into three broad bands, and which one you fall into changes the price per cubic metre.

A full load is the cheapest per m³. If your pour is a neat multiple of 6 m³, you're getting the best rate.

A part load is anything less than a full truck, and it carries a part-load charge, typically a fixed surcharge per cubic metre below the full-load quantity. The truck still has to make the trip, so you pay for the shortfall.

A short load or mini-mix supply, usually under about 2 m³, is delivered by a smaller volumetric or mini-mixer, and is priced differently again. For a small domestic job, a mini-mix or volumetric supplier that mixes on site to the exact quantity is often cheaper and less wasteful than a part load on a full-size truck, because you pay for what you use.

Takeaway: a part load costs a surcharge for the empty space on the truck, so on small pours compare a mini-mix or volumetric quote before defaulting to a standard mixer.

It's tempting to order the exact calculated volume, especially when you're trying to avoid a part load. Don't. Concrete gets lost between the drawing and the pour in ways that are entirely normal: spillage off the chute, an over-dig where the formwork bulged, uneven sub-base leaving the slab deeper in places, and concrete left clinging in the barrow and the truck.

A 5 to 10% waste allowance covers it on most jobs. Tighter, well-formed pours onto a clean sub-base sit at the lower end; footings dug by machine into variable ground sit at the higher end, because trenches are never quite the width the drawing says.

The reason this matters more for concrete than for most materials is that you cannot top up a cured pour. Run 0.3 m³ short on a slab and you don't finish it tomorrow with a bag of mix, you get a cold joint or a re-pour. Being slightly over is cheap. Being slightly under is expensive.

Takeaway: add 5–10% waste even when it nudges you into a part load — a small surcharge is far cheaper than a cold joint or a second pour.

A concrete driveway in Leeds, 10 m long by 4 m wide, laid 150 mm thick.

On a large pour needing three or more loads, the loads aren't independent deliveries you can take whenever. Concrete starts going off from the moment it's batched, and the UK guidance is generally to have it placed within about two hours of batching, less in hot weather. That means the trucks need to arrive in sequence, spaced so each is discharged before the next arrives but not so far apart that a cold joint forms between one load and the next in the same continuous pour.

This is a conversation with the supplier's transport desk, not something you work out alone. Tell them it's a continuous pour, give them the total and the number of loads, and they'll stagger dispatch. What you should not do is book all three for the same slot and hope, because three full mixers arriving together with nowhere to stand is its own expensive problem.

Takeaway: for multi-load continuous pours, book staggered dispatch with the supplier so each load is placed before the next arrives and within the two-hour window.

A full mixer is a heavy, wide vehicle. Before you count loads, check it can actually get to the pour. The chute on a standard truck reaches only a few metres from the back of the drum, so if the pour is beyond that you're either barrowing every cubic metre by hand, which is slow and needs bodies, or paying for a concrete pump, which adds cost but saves a day of wheeling barrows.

Firm standing matters too. A loaded mixer will sink into a soft verge or crack a thin domestic driveway. Suppliers will often refuse to drive onto ground they judge unsafe, and they're within their rights to.

Takeaway: confirm the truck can reach within chute distance of the pour on firm ground before you order — otherwise budget for a pump or the labour to barrow it.

Here's the point most truck-load guides skip, and it's the one worth planning around. The headline advice is "round up to whole loads," which is correct, but it quietly frames the final part load as a rounding detail. On UK pricing it's often the most expensive concrete on the job per cubic metre, because the part-load surcharge is spread over a small quantity.

A groundworker I spoke to put it plainly: he designs the pour to the truck, not the truck to the pour, wherever the specification gives him room. If a slab can be 5.9 m³ instead of 6.4 m³ without dropping below spec, he'll take the version that fits one full mixer every time, because the alternative is paying a surcharge to deliver half a barrow of concrete on a second truck. When the volume can't be trimmed, he switches to a volumetric supplier rather than swallow the part-load rate. His view was that the arithmetic of "how many loads" is easy, and the money is entirely in whether the last load is a full one.

Takeaway: design the pour to land on a full load where the spec allows, and where it can't, put the part load out to a volumetric quote — the last load is where the price hides, not the first.

Work out your total volume, add 5–10% waste, then divide by the truck capacity and round up. The concrete truck load calculator does exactly that, and also shows the remainder on the final load as a volume and as a percentage of the truck, so you can see at a glance whether that last delivery is a full load or an expensive splash. If you haven't worked out the volume yet, start with the concrete volume calculator and bring the figure across.

None of this replaces confirming the order with your supplier, who knows their own truck sizes, access limits and part-load rates. Treat the calculator as the planning step before that call, not a substitute for it.