What is an axle load calculator?
An axle load calculator compares the weight on each axle or axle group of a truck with the limit that applies to it, and the total with the gross weight limit. A truck can be under its gross limit and still overload one axle if the load sits too far forward or back. This calculator gives a ready, check or stop verdict from your weights and your limits, and says whether moving the load could fix an overload or weight has to come off.
Two more tabs help before loading: the load position tab works out front and rear axle loads on a rigid truck from where the load sits, and the load fit tab checks payload capacity, volume and pallet positions.
This tool does not contain legal limits. Limits differ by country, road, vehicle configuration, tires and permits. Enter the limits that apply to your vehicle and route.
Why truck weight distribution across axles matters
- Overloaded axles wear roads, tires and brakes faster and change how a truck steers and stops.
- Weight checks can stop a truck on the road, with delays, re-loading and possible penalties depending on local rules.
- Gross weight is not enough. A load placed too far back can overload the rear axle while leaving the front light, which also affects steering.
- Payload planning saves trips. Knowing whether weight, volume or floor space runs out first lets you fill vehicles better without crossing any limit.
What data do you need to calculate axle loads?
| Input | Where to find it | Tip |
|---|---|---|
| Weight per axle group | Weighbridge ticket, axle scales, on-board weighing | Weigh each group separately, with the truck level. |
| Your limits | Local regulations, vehicle plate, permits, customer site rules | Use the lowest limit that applies, including tire and manufacturer ratings. |
| Empty axle weights | Weighbridge with fuel, driver and equipment | Re-weigh after changing the body or fitting equipment. |
| Wheelbase and load position | Vehicle specification, load plan | Measure from the front axle center to the center of the load weight. |
| Load space and pallets | Body specification, shipping documents | Use inside dimensions and the actual pallet size. |
How to calculate axle loads and weight distribution
Axle group check
A group is over above 100% of its limit, and close from the warning level you set. If an axle is over but gross is within its limit and the other groups have enough margin, moving the load may fix it. If gross is over, weight has to come off.
Load position on a rigid truck
This is the lever rule. Solving it for the limits gives the range where the center of the load can sit:
Capacity and load fit
Worked example: truck and trailer, then a rigid truck
A truck and trailer are weighed before departure. The limits below are example values entered by the operator, not legal limits.
- Steer axle 6,600 kg against 7,100: 93%, within limit. Drive tandem 18,400 kg against 18,000: over by 400 kg. Trailer tri-axle 23,100 kg against 24,000: 96%, close.
- Gross is 48,100 kg against a 48,000 kg limit: over by 100 kg. The verdict is stop: at least 100 kg has to come off, and the rest of the drive axle excess has to move to groups with room.
- On a rigid truck with a 5.5 m wheelbase, 4,200 kg empty on the front and 2,800 kg on the rear, a 9,000 kg load centered 3.6 m behind the front axle puts 5,891 kg on the rear and 3,109 kg on the front. The front axle carries 7,309 kg, over a 7,100 kg limit.
- With limits of 7,100 kg front and 11,500 kg rear, the load center has to sit between 3.73 m and 5.32 m behind the front axle. Moving it back to at least 3.73 m brings the front within its limit.
- A shipment of 12,800 kg, 48 m³ and 18 pallets (1.2 × 1.0 m) on a truck with 14,500 kg payload and a 9.6 × 2.45 × 2.6 m body uses 88% of payload, 78% of volume and all 18 floor positions. It fits, and floor space is the limit.
How to read your axle check results
- Ready means every group and gross are below your warning level.
- Check means at least one is close to its limit. Scales differ, and fuel and load can shift, so leave a margin.
- Stop means at least one is over. The result says whether moving the load could fix it or how much has to come off.
- The allowed load center is the range to aim for when planning where goods go on the deck.
- The limiting factor in load fit tells you whether to plan by weight, volume or floor space for this type of load.
Common mistakes in axle load planning
- Checking gross weight only. A truck under gross can still have an overloaded axle.
- Using the empty weight from the brochure. Bodies, equipment, fuel and the driver change it. Weigh your own truck.
- Forgetting that loads change on the trip. Partial deliveries move the center of the remaining load and can overload an axle that was fine at departure.
- Ignoring the steer axle. A load placed too far back can leave the front axle too light for safe steering.
- Assuming another country's limits. Always use the limits that apply where the truck will run.
Assumptions and limits
Results are estimates based on the values entered, not legal or compliance advice. The calculator uses only the limits you provide and does not know the rules for your vehicle, road or permit. The load position tab models a two-axle rigid truck with the load treated as a single weight; tandems are treated as one point at their center, and articulated vehicles need a different calculation through the fifth wheel. Weighbridge readings remain the reference before departure.