Side-by-side dimensional weight comparison. Same package, two carriers — see exactly what each would bill, and which wins for your shipment profile.
Awaiting dimensions. Enter package details to compute billable weight.
Both carriers use the same divisor (6000 cm³/kg) — the DIM weight will be identical. The price difference will come from base rates, surcharges, and delivery speed.
| Canada Post | USPS | |
|---|---|---|
| Imperial divisor (in³/lb) | Metric only | 166 |
| Metric divisor (cm³/kg) | 6000 | 6000 |
| DIM applies | No minimum | 1,728 in³ (1 ft³) |
| Region | Canada | United States |
Domestic Canadian shipments, US-Canada cross-border, predictable volumetric pricing
Small or heavy dense packages, Flat Rate boxes, light-volume shippers
Divisors don't tell you everything — base rates, fuel surcharges, and discounts also matter.
Canada Post ↗
USPS ↗
It depends on your package. Canada Post's divisor is 6000 cm³/kg, while USPS's is 6000 cm³/kg. For DIM-weighted packages (lightweight bulky), the carrier with the higher divisor wins on billable weight. For dense packages where actual weight wins, the divisor doesn't matter and the cheaper base rate wins. Use the calculator above to see which gives you the lower billable weight for your specific package.
The formula is the same: volume divided by the divisor, rounded up, with the billable weight being the greater of the result or the actual weight. The divisors differ (6000 cm³/kg for Canada Post, 6000 cm³/kg for USPS), which is what produces different billable weights for the same package.
Yes — many shippers use both, routing each package to whichever carrier is cheaper for that shipment profile. Multi-carrier rate-shopping platforms (Shippo, ShipStation, Easyship) automate this decision in real time based on weight, dimensions, destination, and your negotiated rates with each carrier.
This page focuses on Canada Post vs USPS. To see how all major carriers compare for your specific shipment, use the main calculator with the global setting.
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