Is Euro 6 the same as ULEZ?

No — Euro 6 and ULEZ are related but not the same thing. Euro 6 is an emissions standard; ULEZ (Ultra Low Emission Zone) is a specific charging scheme that uses emissions standards, among other things, to decide which vehicles pay a charge.

How they relate:

• Euro 6 (diesel) and Euro 4 (petrol) are generally the minimum standards a vehicle needs to meet to avoid the ULEZ daily charge in London, though other cities and clean air zones across the UK have their own schemes with sometimes different rules
• Meeting Euro 6 doesn't automatically mean a vehicle is exempt from every clean air zone in the country — different zones can apply different rules, charges, and exemptions
• ULEZ and similar zones are administered locally (by Transport for London, in ULEZ's case, or the relevant local authority for other zones), while Euro standards are a broader, nationally and EU-wide applied emissions classification

Why this distinction matters:

If you're checking whether a specific journey will incur a charge, it's worth checking the specific scheme's rules directly (for example, via Transport for London's ULEZ checker, or the relevant local authority's clean air zone checker) rather than assuming Euro 6 status alone guarantees exemption everywhere, since rules and charges can vary meaningfully between different UK cities and zones.