Weight & Axle Distribution Calculator
Check if your loaded truck meets federal weight limits. Calculates gross vehicle weight, weight per axle, and flags overweight conditions.
Results
Visualization
How It Works
Federal law limits the gross vehicle weight (GVW) of commercial trucks to 80,000 pounds on interstate highways. Individual axle limits also apply: 12,000 lbs for a single steer axle, 34,000 lbs for a tandem axle group. Overweight violations carry steep fines, and repeated offenses can put your carrier out of service. This calculator estimates total weight and axle distribution to help you stay legal.
The Formula
Avg Per Axle = GVW / Number of Axles
Steer Axle (est.) = Truck Weight x 35%
Drive Axles (est.) = (Truck Wt x 65%) + (Cargo x 25%)
Trailer Axles (est.) = Trailer Wt + (Cargo x 75%)
Variables
- GVW — Gross Vehicle Weight: total combined weight of tractor, trailer, and cargo
- 80,000 — Federal maximum GVW in pounds for interstate highways
- 12,000 — Maximum weight on a single steer axle (lbs)
- 34,000 — Maximum weight on a tandem axle group (lbs)
Worked Example
An 18,000 lb tractor with a 14,000 lb trailer hauling 40,000 lbs of cargo has a GVW of 72,000 lbs. This is 8,000 lbs under the 80,000 lb limit with a utilization of 90%. Average per axle on 5 axles is 14,400 lbs.
Practical Tips
- Always weigh your truck at a CAT scale before entering a state with strict enforcement. It costs $12-15 and can save thousands in fines.
- Slide your tandems to redistribute weight between drive and trailer axles. Each hole moved shifts roughly 500 lbs.
- Some states allow higher weights on certain highways or with permits. Check state DOT websites for specific limits.
- Overweight fines can range from $100 to $16,000 depending on the state and how far over the limit you are.
- Liquid loads shift during transit. Account for surge and slosh effects that can temporarily overload individual axles.
Frequently Asked Questions
What is the maximum weight for a semi-truck?
The federal limit is 80,000 lbs GVW on interstate highways. This includes the tractor, trailer, and all cargo. Some states allow higher weights on non-interstate roads with permits.
How much cargo can a typical semi haul?
With a tractor weighing 18,000 lbs and a trailer at 14,000 lbs, a standard 5-axle combo can carry about 48,000 lbs of cargo before hitting the 80,000 lb limit.
What are the fines for overweight trucks?
Fines vary by state but typically start at $100-$300 for minor violations (under 2,000 lbs over) and can exceed $10,000 for egregious violations. Some states charge per-pound penalties.
What are the individual axle weight limits?
Federal limits are 12,000 lbs for a single steer axle, 20,000 lbs for any single axle, and 34,000 lbs for a tandem axle group.
How do I redistribute axle weight?
Slide the trailer tandems forward to shift weight to the trailer axles, or backward to shift weight to the drive axles. Each hole adjustment moves approximately 400-500 lbs.