Axle Weight Limit Calculator

About the Axle Weight Limit Calculator

Federal law limits commercial vehicle weights: 12,000 lbs on the steer axle, 34,000 lbs on a tandem (drive or trailer), and 80,000 lbs gross vehicle weight. States may have stricter limits, especially on secondary roads and posted bridges. Exceeding any single limit triggers fines and potential out-of-service orders.

Drivers and dispatchers must verify axle weights before departing the shipper. Even a load under the 80,000 lb GVW can have an individual axle overweight due to improper weight distribution. This is one of the most common citations at weigh stations.

This calculator lets you enter actual or estimated axle weights and quickly see whether each axle group complies with federal limits. Use it before departing to avoid costly fines, out-of-service delays, and unsafe driving conditions.

Use the result to compare operating scenarios, pressure-test assumptions, and rerun the model when volumes, rates, or service targets change.

When This Page Helps

Overweight fines average $1-$10 per pound over the limit depending on the state. A truck 3,000 lbs over on drives could face a $3,000-$10,000 fine. This calculator takes 30 seconds and can save thousands in penalties.

How to Use the Inputs

1. Enter your steer axle weight.
2. Enter your drive tandem weight.
3. Enter your trailer tandem weight.
4. View each axle's compliance status.
5. Check the total GVW against 80,000 lbs.
6. Adjust load placement if any axle is over the limit.

Example Calculation

Tips & Best Practices

• Always weigh at a CAT Scale before heading to a weigh station if near limits.
• Slide 5th wheel or trailer tandems to redistribute weight between axle groups.
• Bridge formula limits may be more restrictive than per-axle limits.
• Some states (Michigan, other Great Lakes states) allow higher weights on designated routes.
• Consider tractor and trailer tare weight when estimating load capacity.
• Fuel weight matters — a full fuel tank adds 1,000-1,400 lbs to the steer/drive axles.

State Weight Limit Variations

While 80,000 lbs GVW is the federal standard, states set their own rules for non-interstate roads. Some states are more restrictive on secondary highways and county roads. Michigan allows up to 164,000 lbs on 11-axle configurations on state highways. Check each state's DOT website for specific limits along your route.

Scale Avoidance vs. Compliance

Some drivers attempt to bypass weigh stations, which is illegal and often detected by weigh-in-motion sensors and PrePass systems. The consequences of scale avoidance (additional citations, higher fines, suspension) far outweigh the cost of compliance.

Proactive Weight Management

Build weight verification into your standard operating procedures: weigh loads at origin (use shipper scales or nearby CAT Scale), adjust weight distribution before departure, and document weights on the BOL. This systematic approach eliminates weigh station surprises.

Frequently Asked Questions

• What is the federal GVW limit?

  The federal gross vehicle weight limit is 80,000 lbs for a standard 5-axle tractor-trailer on interstate highways. This includes the weight of the tractor, trailer, fuel, driver, and all cargo. Some states allow higher weights with permits or on designated routes.

• What are the per-axle limits?

  Federal limits: single axle ≤ 20,000 lbs, tandem axle ≤ 34,000 lbs. The steer axle is effectively limited to 12,000-12,500 lbs by tire ratings. The bridge formula may further restrict weight based on axle spacing.

• What happens if I'm overweight at a weigh station?

  The truck is held until the overweight condition is corrected. Fines are assessed per state law — typically $1-$10 per pound over. The driver may also receive a citation affecting their CDL record. The carrier's safety score is impacted.

• Can I get a permit for overweight loads?

  Yes. Most states issue overweight permits for loads that cannot be reduced. Permits typically cost $20-$200+ depending on weight, distance, and route. The load must follow a specified route, often restricted to highways and limited to daytime hours.

• How does tandem axle spacing affect limits?

  Tandems spaced less than 8 feet are treated as a single axle group (20,000 lb limit). At 8+ feet spacing, the tandem limit of 34,000 lbs applies. Wider spacing allows more weight under the bridge formula.

• How much does fuel weigh?

  Diesel weighs about 7 lbs per gallon. A full 150-gallon fuel tank adds approximately 1,050 lbs, primarily on steer and drive axles. When running near weight limits, fuel level can make the difference between legal and overweight.