Guides · LoadLegit · 2026-08-03

Canadian truck weight limits: the interprovincial MOU explained

Canada regulates truck weights very differently from the United States. There is no single federal weight law and no bridge formula. Instead, weights are set by each province and territory, then harmonised through the Memorandum of Understanding on Interprovincial Weights and Dimensions — the "MOU," coordinated by the Council of Ministers Responsible for Transportation (COMT). Every province agrees to accept an MOU-compliant vehicle on a designated interprovincial highway network, and everything is measured in kilograms and metres.

The MOU limits for a Category 1 tractor-semitrailer

For the standard 5-axle tractor-semitrailer (single steer, tandem drive, tandem trailer):

That 39,500 kg gross is about 87,080 lb — meaningfully more than the US 80,000 lb limit. Canada allows the heavier rig because it governs by axle-group limits and axle spacing, not by a bridge formula.

Six axles: the tridem trailer

Swap the trailer tandem for a tridem (three closely spaced trailer axles) and the limits rise, scaled to how far apart the tridem axles are:

The wider the tridem spread, the more weight it may legally carry — the same "spread the load out" principle the US bridge formula captures, but expressed as fixed bands instead of an equation.

No bridge formula — spacing and group limits instead

In the US, the Federal Bridge Formula can fail a truck that passes every individual axle limit. Canada has no equivalent calculation. As long as each axle group is within its MOU limit and the axle spacings fall in the allowed windows, the configuration is legal on the interprovincial network. That makes Canadian compliance simpler to check — but the numbers are entirely different, so you can't reuse US limits north of the border.

Provinces can allow more

The MOU is a floor for interprovincial travel, not a ceiling. On their own highway networks, provinces often permit heavier or longer configurations (special permits, SPIF vehicles in Ontario, resource roads, and so on). Always confirm the province you're running in — the MOU guarantees acceptance across borders, but a province may allow more at home.

Check a Canadian load in seconds

Enter your axle weights in kilograms and our free calculator checks them against the MOU limits — switch it to Canada mode for metric input and MOU rules (no bridge formula). For province-by-province specifics, see our Canadian province weight guides, and if you run both sides of the border, read US vs Canada truck weight limits.

Compliance guidance, not legal advice — always confirm with the governing province or territory before you roll.