Truck weight limit checker
Enter your axle weights from a scale ticket and the distance between axles. The checker compares each axle group and your gross with the federal Interstate limits and the Bridge Formula.
Updated October 2026 · Free, no signup
Federal Interstate check
- Steer: 12,000 lb / 20,000 lb
- LEGAL
- Drive: 34,000 lb / 34,000 lb
- LEGAL
- Trailer: 34,000 lb / 34,000 lb
- LEGAL
- Gross: 80,000 lb / 80,000 lb
- LEGAL
- Steer: Single axle
- Drive: Tandem axle
- Trailer: Tandem axle
- Gross: Interstate gross limit
Federal limits apply on the Interstate System. Off the Interstate, your state's limits apply and can be lower or higher.
State limits: not yet verified on this site. Check your state DOT, listed on FHWA's state permit contacts.
Legal at 80,000 lb gross. We only offer loads that fit your truck's legal weight, and you confirm every one before it's booked.
Get load offers that fit my truckHow the checker works
The checker uses the federal weight limits that apply on the Interstate System:
| Limit | Federal Interstate value |
|---|---|
| Single axle | 20,000 lb |
| Tandem axle | 34,000 lb |
| Gross vehicle weight | 80,000 lb |
| Any group of 2+ axles | Bridge Formula |
Source: 23 CFR 658.17 (FHWA) · checked 2026-10
The Bridge Formula sets the most weight a group of axles can carry based on how many axles there are and how far apart they sit:
W = 500 x (L x N / (N - 1) + 12N + 36), where W is the maximum weight in pounds, L is the distance in feet between the outer axles of the group, and N is the number of axles. The checker rounds to the nearest 500 lb, as FHWA's tables do.
Source: FHWA Bridge Formula Weights · checked 2026-10
For each axle group, the checker compares your weight with the single, tandem or Bridge Formula limit. For the whole truck, it uses the lower of 80,000 lb and the Bridge Formula for all axles over your outer bridge length.
Worked example: a tandem dump truck
| EXAMPLE | Weight | Limit | Result |
|---|---|---|---|
| Steer axle | 18,000 lb | 20,000 lb | Legal |
| Rear tandem | 33,000 lb | 34,000 lb | Legal |
| Gross, 3 axles over 20 ft | 51,000 lb | 51,000 lb (Bridge Formula) | Legal, at the limit |
Add 4,000 lb to the rear and the tandem goes over by 3,000 lb and the gross by 4,000 lb, even though the truck is nowhere near 80,000. Short trucks run out of bridge long before they run out of gross.
What the results mean
LEGAL means within the federal limit for that group on the Interstate. It doesn't mean legal everywhere: on state and local roads, your state's limits apply, and some states allow more under grandfather rules or with specific axle setups.
OVER means don't move it as loaded. Shift weight between axles (slide the fifth wheel or tandems), take load off, or for a load that can't be divided, get the permit your state requires before you move. This site never suggests running overweight.
State limits
We haven't verified state-by-state limits for this tool yet, so it doesn't guess. Each state's permit office and rules are listed on FHWA's state oversize and overweight permit contacts page.
Getting accurate axle weights
Weigh on a certified scale and get a ticket that shows each axle group. Weigh loaded, with full fuel. If you can't reach a scale, the axle weight calculator estimates how a load spreads across axles, but a scale ticket is the only number an inspector accepts.
Questions about this calculator
What is the legal weight limit for a semi truck?
On the Interstate System, federal limits are 20,000 lb on a single axle, 34,000 lb on a tandem axle and 80,000 lb gross, and the Bridge Formula can lower the gross for short wheelbases. A standard 5-axle tractor-trailer needs about 51 ft between the first and last axles to reach 80,000 lb. States set limits on other roads.
How much weight can a dump truck carry legally?
It depends on the axles, their spacing and the roads. A tandem dump with about 20 ft between its first and last axles is held to 51,000 lb gross by the Bridge Formula on the Interstate, even if each axle group is legal. Many states allow more on state roads or under grandfather rules. Check your state.
Do federal weight limits apply on every road?
No. The federal limits in 23 CFR 658.17 apply to the Interstate System, and states must follow them there. On other roads, each state sets its own limits, which can be higher or lower. Some states also keep grandfathered limits on their Interstates.
What happens if my truck is overweight?
Fines, a stop at a scale, and often an order to shift or remove load before you can move. Overweight trucks also wear brakes, tires and roads faster and are harder to stop. Fix the load before you leave the scale. We never offer loads that would put you over.
Can I get an overweight permit?
States issue permits mainly for loads that can't be broken down, like a large machine. Loads you can divide, such as aggregate or general freight, usually can't be permitted over federal limits on the Interstate. Each state runs its own permit office; FHWA lists their contacts.
Numbers done. Want someone to find loads that beat them?
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