Axle weight limit checker (federal)
Check steer, drive, and trailer axle weights plus gross weight against the US federal limits: 20,000 lb single, 34,000 lb tandem, 80,000 lb gross.
Over a limit — or want to prove you're under? Create a free account to get the exact tandem slide that makes a load legal, plus a shareable PDF certificate. 25 checks free, no card.
US federal axle weight limits
| Axle group | Federal Interstate limit |
|---|---|
| Single axle | 20,000 lb |
| Tandem axle group | 34,000 lb |
| Gross vehicle weight (GVW) | 80,000 lb |
These are the Interstate maximums in 23 CFR 658.17. In practice a steer axle is usually limited well below 20,000 lb by the tires and front-axle rating — 12,000–13,200 lb is typical.
This checker covers the three federal caps only. Individual axle spacing (the Bridge Formula), state limits, and permit rules can be stricter or more generous. Michigan, for example, permits far higher gross weights on additional axles. Run a full LoadLegit check for the governing verdict in your state.
Check a real load in secondsLoadLegit turns axle weights into a pass/fail compliance verdict — federal Bridge Formula plus verified state and Canadian rules — and issues a shareable certificate. Try it free →
Frequently asked questions
What is the legal single axle weight limit?
On the US Interstate system the federal single-axle limit is 20,000 lb. In practice a steer axle is usually limited well below that (12,000–13,200 lb) by its tires and rating, and some states set different single-axle numbers on non-Interstate roads.
What is the maximum tandem axle weight?
The federal Interstate tandem limit is 34,000 lb. Axle spacing can reduce it under the bridge formula, and a few states allow more on non-Interstate roads (for example Ohio's spacing scale reaches 40,000 lb on two axles).
What is the maximum legal weight for a semi truck?
The federal gross-weight limit is 80,000 lb for a standard 5-axle tractor-semitrailer without a permit. You also have to meet the 20,000 lb single / 34,000 lb tandem limits and the bridge formula for every axle group.
Are state axle weight limits the same as federal?
On Interstates, yes — federal limits govern nationwide. Off the Interstate, states vary: some match federal, others (Michigan, Ohio, New York, Georgia and more) have their own higher or lower numbers. Check the specific state page for the governing rule.
Can I be under 80,000 lb and still be overweight?
Yes. Gross weight is only one of the limits. If a single axle or tandem group is over its cap — or the bridge formula is violated for a set of axles — the load is illegal even at, say, 76,000 lb gross. Rebalancing the load or sliding the tandem fixes it.
Related
Federal Bridge Formula calculatorFree Federal Bridge Formula calculator. Enter axle count and the spacing between the extreme axles to get the maximum legal weight (W = 500(LN/(N-1)+12N+36)).What is gross vehicle weight (GVW)?Gross vehicle weight (GVW) is the total actual weight of a fully loaded vehicle — tractor, trailer, fuel, driver and cargo. The federal Interstate limit is 80,000 lb.What is a tandem axle?A tandem axle is two axles spaced close together (typically 40–96 inches) that share a load as one group. The US federal tandem limit is 34,000 lb.What is the steer axle?The steer axle is the front, steered axle of a truck. Federally it may carry up to 20,000 lb, but tires and the front-axle rating usually limit it to 12,000–13,200 lb.