Is kerb weight the same as unladen weight?

Not quite — kerb weight and unladen weight are closely related, but they're measured slightly differently, and the distinction can matter for tax and legal purposes.

The difference:

• Kerb weight — the modern, commonly used measure: the vehicle ready to drive, including a full tank of fuel, oil, coolant, and standard equipment, but without driver, passengers, or cargo
• Unladen weight — an older legal definition still used in some tax and licensing contexts, referring to the vehicle without fuel, driver, passengers, or load, and sometimes excluding certain standard equipment depending on the exact legal definition applied

Why this matters:

For most everyday purposes — like general reference or comparing cars — the two figures are close enough that people use them interchangeably. But unladen weight specifically still appears in some older tax classifications and legal contexts (particularly around older vehicles or specific vehicle categories), where the precise definition can affect which rules apply. If you're relying on a weight figure for a specific legal or tax purpose rather than general reference, it's worth checking which definition is actually being used on that document, since the terms aren't always used consistently across older and newer paperwork.