"How much dirt fits in a 12-wheeler?" It's the question everyone asks before ordering a truckload of dirt. You want to raise your yard, fill a hole or level your lot, and you don't know if it takes three loads or ten. The short answer: a 12-wheeler carries around 19 tonnes of dirt, which works out to roughly 15 to 18 cubic yards in the box. But that number shifts with the material, the moisture and the season.
Terreadonner, a service of Groupe Eazyvrac, connects excavators who have dirt to place with receivers who can take it. Here's how it works, with sourced figures and a sample calculation you can redo at home.
How many tonnes in a 12-wheeler and in a 10-wheeler
In Quebec, what limits a dirt truck is first its weight, not the size of its box. The provincial regulation on load limits sets the gross vehicle weight (truck + load):
- 10-wheeler (3-axle truck, one front axle and a rear tandem): 25,250 kg maximum.
- 12-wheeler (4-axle truck, two steering axles up front and a rear tandem): 31,000 to 32,000 kg maximum, depending on the spacing of the front axles.
The truck itself is pretty heavy. In its bulk trucking handbook, the Ministère des Transports uses a net weight of 10,750 kg for a 10-wheeler and 12,750 kg for a 12-wheeler. What's left for the dirt is the payload:
| Truck | Payload outside thaw period | Payload during thaw period |
|---|---|---|
| 10-wheeler (3 axles) | 14.5 tonnes | 12 tonnes |
| 12-wheeler (4 axles) | 19.25 tonnes | 16.75 tonnes |
Keep this in mind: in spring, during the thaw period, allowed loads go down. The same 12-wheeler brings less dirt in April than in August. And every truck has its own empty weight, so ask the trucker what he can load.
How many cubic yards (and cubic metres) in a dirt truck
This is where it gets tricky, because a cubic metre of dirt doesn't always weigh the same. The reference handbook from Caterpillar, an earthmoving equipment manufacturer, gives these densities for earth and clay once loaded ("loose" dirt): between 1,420 and 1,660 kg per cubic metre depending on the material and its moisture. The same dirt, in the ground before it's dug ("in-place" or "bank" dirt), weighs more like 1,660 to 2,080 kg per cubic metre. Caterpillar says it itself: weight varies with moisture, grain size and compaction.
Conversion reminder:
- 1 cubic yard = 0.7646 cubic metre
- 1 cubic metre = 1.308 cubic yards
Dividing the payload by those densities gives:
| Truck (outside thaw) | Volume in the box (loose dirt) | Volume once in place |
|---|---|---|
| 10-wheeler, 14.5 t | 8.7 to 10.2 m³ (11 to 13 yards) | 7 to 8.7 m³ (9 to 11 yards) |
| 12-wheeler, 19.25 t | 11.6 to 13.6 m³ (15 to 18 yards) | 9.3 to 11.6 m³ (12 to 15 yards) |
As for boxes, manufacturers offer every size for heavy trucks: Crysteel's Paradox/Raptor line, for example, runs from 13 to 26.9 yards. A big box filled to the brim with wet clay would quickly go over the allowed weight. That's why we talk in tonnes first, yards second.
Swell and settling: why dirt "changes volume"
When you dig dirt, it swells: the air between the grains takes up room. That's called swell. Caterpillar expresses it with a "load factor": for earth and clay, it runs around 0.79 to 0.85. In other words, 1 cubic metre dug becomes about 1.18 to 1.27 cubic metres in the box.
The other way around, once spread at your place, the dirt settles with weight, rain and time. If you compact it, it even gets denser than it was originally. Result: if you order 10 cubic metres "in the box" to fill a 10-cubic-metre hole, you'll come up short.
The simple rule: calculate the volume you need once in place, convert it to tonnes, then divide by the truck's payload.
How to calculate the number of loads for your lot
Take a 15 m × 10 m yard that you want to raise by 30 cm.
1. Area: 15 m × 10 m = 150 m²
2. Thickness in metres: 30 cm = 0.30 m
3. In-place volume: 150 m² × 0.30 m = 45 m³, or 45 × 1.308 = 58.9 cubic yards
4. Weight: 45 m³ × 1,660 to 2,080 kg/m³ = about 75 to 94 tonnes
5. Loads by 12-wheeler (19.25 t): 75 ÷ 19.25 = 3.9 and 94 ÷ 19.25 = 4.9, so 4 to 5 loads
6. Loads by 10-wheeler (14.5 t): 75 ÷ 14.5 = 5.2 and 94 ÷ 14.5 = 6.5, so 6 to 7 loads
In the boxes, those 45 m³ represent around 56 m³ of loose dirt (45 ÷ 0.80), or about 74 yards. Don't be surprised if the pile looks huge on delivery day: it will go down.
Rather not pull out the calculator? The site has a calculator right on the home page: enter your dimensions and it does the math for you.
10-wheeler or 12-wheeler: which one to choose?
The 12-wheeler brings about 33% more per load (19.25 t versus 14.5 t). For a big fill job, that means fewer round trips up your driveway. The 10-wheeler is shorter and easier to manoeuvre: it fits better in a narrow driveway or a tight yard.
Before choosing, look at the ground itself. The Terreadonner team's experience: when the ground is too soft after rain, the truck breaks through and gets stuck. A loaded 12-wheeler is more than 30 tonnes on your driveway, and on your lawn. Plan a firm spot to dump.
What Terreadonner changes for you
On Terreadonner, there are free offers and paid offers: get informed and set your requirements before accepting a load.
Are you a receiver? Registration is free. You describe your lot (where it is, how much you can take, truck access) and excavators in the area see your request. Whether you're in Montreal, Laval or Longueuil, local guides are waiting for you too: Montreal, Laval, Longueuil.
Are you an excavator? Post your surplus, or do your own search among the lots that can take it.
FAQ
How many yards in a 12-wheeler?
Around 15 to 18 cubic yards of loose dirt in the box, outside the thaw period. It varies with the material and the moisture.
How many tonnes in a 10-wheeler?
The Ministère des Transports uses a payload of 14.5 tonnes outside the thaw period and 12 tonnes during the thaw period.
How much does a cubic metre of dirt weigh?
According to Caterpillar, 1,420 to 1,660 kg once loaded, and 1,660 to 2,080 kg in place, for earth and clay. Moisture makes a big difference.
Why order in tonnes rather than yards?
Because the truck is limited by its allowed weight. A box full of wet clay can weigh much more than a box of dry dirt.
Is it a big deal to order too much dirt?
It can get expensive. The Terreadonner team's experience: hauling the surplus back out can cost about $500 per truck. Do the math first.
Conclusion
A 12-wheeler is around 19 tonnes, or 15 to 18 yards in the box and 12 to 15 yards once in place. A 10-wheeler, around 14.5 tonnes. Start from your area, multiply by the thickness, convert to tonnes, and divide by the truck's payload. Keep a margin for the material and the moisture, and think about the thaw period if you're receiving in spring. With these numbers in hand, you speak the same language as the trucker.