How much does a dump truck carry, and how to work out how many loads you need
A dump truck's capacity is expressed in cubic metres for volume and in tonnes for weight, and the real limit is the weight permitted on the road, not the volume of the body. For heavy materials such as ballast, the weight limit is reached before the body is full.
It is one of the most common sources of misunderstanding on a job: the client calculates in cubic metres, the haulier invoices in tonnes, and at the end the figures do not match. Here is how they relate.
Volume and weight are not the same thing
A cubic metre measures the space occupied. A tonne measures weight. A cubic metre of dry sand weighs much less than a cubic metre of wet ballast.
That is why a dump truck is not loaded “to the brim” regardless of the material: with heavy materials, the legal axle weight limit is reached before the body is full. With light materials, it is the other way round — the body fills up before the weight limit is reached.
The practical conclusion: ask the haulier how many tonnes they load for your material, not just how many cubic metres the body holds.
Bulking: the trap with excavations
Soil in the ground is naturally compacted. When you dig it, it loosens — the same soil takes up more space than it did in the ground.
This means that a 20 cubic metre pit produces more than 20 cubic metres of soil to remove. The difference varies with the type of soil, but it is significant.
The same logic applies in reverse to fills: to fill a volume and then compact it, you need more material than the empty volume, because the material gets denser.
Anyone who calculates the exact volume of the pit and orders exactly that many loads ends up with soil left in the yard.
How to calculate correctly
- Calculate the theoretical volume: length × width × depth.
- Add the bulking margin for excavations, or the compaction margin for fills.
- Ask the haulier how many tonnes or cubic metres they actually load for that material.
- Divide and round up.
What affects the cost of transport
- the round-trip distance to the loading point or to the tip
- waiting time during loading and unloading
- access — if the dump truck cannot get into the yard, it unloads at the street and the material is moved with another machine
- the type of material, for debris that goes to an authorised tip
Mistakes that cost money
Ordering “about three trucks”. Without a calculation, either material is left in the yard or the work stops for another trip.
Forgetting about access. An 8×4 dump truck needs room to manoeuvre and a road that can take its weight. On soft ground it gets stuck.
Forgetting where it is unloaded. Material unloaded in the wrong place has to be moved a second time, with a machine — double the cost for nothing.
What we do
We transport aggregates and remove soil or debris with MAN 8×4 dump trucks, loaded with our own machinery. If you tell us the dimensions of the job, we will work out how many loads are needed.
Have a job in mind?
Describe it to us and get a quote the same day. Equipment with operator, from a single day.