AxleSet
Axle weight & tandem slide calculator for truckers
Free, with no counter and no account: the whole calculation against the federal limits — the bridge formula, the tandem and fifth-wheel slide and the full advice — your rig with its calibration, how it works, and the scale directory. The free card never says just "legal": it says you are within the federal limits and that your state can be stricter, because the federal number is not your state's number.
AxleSet Pro opens your state: all 50 and the District of Columbia with the legal citation for each, the kingpin rule, the APU allowance, the tolerance a state's law grants as a right, the road classes — plus the saved-ticket file (photo, PDF, CSV, iCloud) and scale correction. It is a subscription: US$6.99 a month or US$39.99 a year, with a 7-day free trial, and it renews on its own until you cancel it. We never see your payment details: the App Store handles all of it.
On your iPhone, open Settings > [your name] > Subscriptions, tap AxleSet and choose Cancel Subscription. Cancel at least 24 hours before the free trial or the current period ends and you will not be charged again; AxleSet Pro stays open until the end of the time already paid for. Deleting the app does not cancel the subscription.
Sign in to the App Store with the same Apple ID, open AxleSet, go to the purchase screen and tap Restore. It brings back an active subscription. If you bought the one-time unlock sold before 26 September 2026, Restore brings that back too: it is yours to keep, with no subscription. AxleSet never restores on its own; it waits for you to tap the button.
From where your tandems are right now. "3 holes forward" means three holes toward the cab from the hole they are in today. "Back" is away from the cab. The fifth wheel works the same way: "forward" is toward the front of the tractor.
Because it depends on your trailer. Weight moved per hole equals the trailer-axle weight times the hole spacing, divided by the kingpin-to-tandem distance. A 53-foot van at 40 feet with 6-inch holes moves about 420 lb a hole; with 4-inch holes, about 280. AxleSet calculates it for the trailer in your rig profile. That is why the profile matters.
In My rig, tap Calibrate from two weighings. Weigh, slide the tandems a known number of holes, weigh again, and type both trailer-axle readings. AxleSet works out the distance from the two numbers.
AxleSet tried every hole and every fifth-wheel notch you told it you have, and none of them gets every axle group under its limit. The card shows the closest it could get and what is still over. That is the moment to rework the load or drop weight — not to reweigh.
The one you pick. Most states have two sets of numbers, Interstate and everything else. Some states write a lower limit for a class of road as well — a county road in Georgia, a Class B road in Wisconsin, Kentucky's AA and A routes, a gravel road in Minnesota, a town highway in Vermont. In those states the road class is another choice on the state screen, with its own limit and its own statute cited, and the verdict is worked with that class. Mississippi has two of them on top of its state-highway numbers: the Blue Line routes, and everything the state has not designated. If you do not know which class you are on, pick the lower one: it is the one that can get you the ticket.
No. A few states write axle limits and a bridge rule but no gross cap at all off the Interstate, and there AxleSet judges you by the axles and the bridge formula and says on the screen that the statute sets no gross cap — it does not invent 80,000 to fill the hole. A few go the other way: Maine, off the Interstate, lets a six-axle rig reach 100,000 lb when it meets the conditions its statute sets, and the screen quotes them. Either way the number on the screen is the one in that state's law, with its citation.
Because the kingpin-to-rear-axle rule does not exist for every trailer. In some states the statute ties it to the length of the semitrailer — mostly to trailers longer than 48 feet, and in a couple of them only to the longest ones. With a shorter trailer AxleSet says the rule does not apply in that state instead of calling you legal under a rule that was never yours; where the law makes no distinction by length, the rule is judged with any trailer. The length lives in My rig, one per trailer, and it starts at 53 feet.
Because in Alaska it is worth 3,000 lb. The state writes two bridge formulas, and the one for a drive group with a lift axle in it does not carry the extra 3,000 lb that the other one does. AxleSet assumes you have one until you say otherwise, which is the strict side, and the answer lives in My rig next to the trailer length.
It is what the statute says. The federal 550 lb allowance is written for the Interstate. Off the Interstate each state decides: many keep the same 550 lb, some write 400 lb — and in Oklahoma that 400 lb lifts the bridge-formula gross only, not the axle or tandem limits. Where a state's law writes no allowance at all, AxleSet counts none and tells you so on the screen: in practice many scales still give 400 lb, but no statute obliges them to, so we do not count weight you may not have. Careful with the charts that quote a figure for the fine: some states write their credit only into how the penalty is worked out, and that is not room to load.
Because two rules can be read on the same load, and we do not hide either. Where a state's own statute is lower than the federal rule on the Interstate, or where a state applies an old 1956 figure that no statute we can read backs up, AxleSet gives the verdict with the number that cannot get you a ticket and shows the other reading right beside it, with the rule it comes from. You are the one on the road: you decide what to do with the second number.
No. AxleSet judges every weight to the legal limit. Some states' statutes grant a tolerance as a right off the Interstate (Vermont on it too). On those roads an option under the strategies adds only the tolerance that road's law grants and shows its condition, and the card says when a position is legal only because of it. Where a state grants none, the option does not appear. The ticket from a certified scale is what counts.
Every limit comes from that jurisdiction's own statute or DOT publication — the District of Columbia's, from its own regulations — or from an archived copy of that official page. The state screen names the source, says which of the two it was, and gives the date it was read. Five states publish their fine schedule only where we could not confirm it officially; there the fines block says "not verified" and shows no dollar figures, while the weight limits above it are unaffected.
The lower number, and it tells you. For example, one federal example and one state table round the same bridge-formula case 500 lb apart; AxleSet shows the lower figure and flags the tie.
More than the number in the statute. In 2025, 167,118 weight citations were written in the United States: 89,883 on an axle against 27,331 on gross — 3.3 axle tickets for every one on gross, which is why a load that grosses fine can still cost you. And the base fine is rarely the bill: one California county court's published 2026 bail schedule turns a $20 statutory fine into $158, and a $175 one into $808; past 4,500 lb of excess, California stops calling it an infraction. Alabama told its own legislators that one truck in five inspected gets a citation and that half of those citations are for weight. AxleSet shows you the state's fine schedule with the statute cited, where the state publishes one — what you pay is decided at the roadside and in that court, not here.
No. The state limits, the fine schedules and the CAT Scale list are built in, and the ticket is read on the phone. The one exception is the optional iCloud backup of rigs and tickets: it uses your own Apple account, and only if you turn it on. That switch only stays on if the first copy really goes up — with no iCloud account signed in on the phone, AxleSet turns it back off and says so, instead of letting you believe there is a copy.
No. AxleSet is a reference and a calculator. Laws change, permits change things, and the officer's table wins at the roadside. When in doubt, check with the state.