Axle Load Distribution Calculator
Calculate per-axle load distribution, check legal compliance, and optimize cargo placement for safe and legal truck transport operations.
Empty vehicle weight including trailer
Axle load distribution refers to how the total weight of a vehicle and its cargo is distributed across each axle. Proper weight distribution is critical for:
Vehicle Stability
Balanced weight distribution ensures proper handling, braking, and prevents rollovers.
Legal Compliance
Each jurisdiction has maximum weight limits per axle that must not be exceeded.
Infrastructure Protection
Overloaded axles cause excessive road and bridge damage, leading to costly repairs.
| Region | Single Axle | Tandem Axle | Max GVW | Notes |
|---|---|---|---|---|
| United States | 20,000 lbs (9,072 kg) | 34,000 lbs (15,422 kg) | 80,000 lbs (36,287 kg) | Federal limits; Bridge Formula applies |
| European Union | 11,500 kg | 19,000 kg | 40,000 kg | Directive 96/53/EC |
| United Kingdom | 11,500 kg | 19,000 kg | 44,000 kg | Higher limit for intermodal transport |
| Australia | 9,000 kg | 16,500 kg | 62,500 kg | B-doubles can operate up to 68.5t |
The Federal Bridge Gross Weight Formula (also known as Bridge Formula B) is used in the United States to determine the maximum allowable weight for a group of consecutive axles based on their spacing. This protects bridges from concentrated loads.
W = 500 × ((L × N) / (N - 1) + 12N + 36)
W
Maximum gross weight on any group of consecutive axles (in pounds)
L
Distance in feet between the extreme axles of any group
N
Number of axles in the group being considered
Key Insight: Longer axle spacing allows for higher weight limits because the load is distributed over a greater length, reducing stress on bridge structures.
Do's
- Distribute cargo weight evenly across the trailer bed
- Position heavy items close to or over the axles
- Maintain at least 20% of GVW on the steering axle
- Verify weight limits for each jurisdiction traveled
- Account for fuel weight changes during the journey
Don'ts
- Concentrate all weight in one area of the trailer
- Exceed individual axle limits even if total GVW is under
- Ignore uneven weight distribution between left and right
- Forget to account for trailer tare weight
- Assume all regions have identical weight limits
Focusing Only on GVW
Even if total weight is under the limit, individual axles can still be overloaded. Always check per-axle weights, not just gross vehicle weight.
Ignoring the Bridge Formula
In the US, the Bridge Formula can limit weights below standard limits for vehicles with closely spaced axles. Always verify compliance with this formula.
Not Accounting for Fuel
A full fuel tank can add 400-600 kg to the steer axle. Weight distribution changes as fuel is consumed during the journey.
Cross-Border Compliance
Different countries and states have different limits. A legal load in one jurisdiction may be overloaded in another.