Last reviewed: September 2026
The New European Driving Cycle (NEDC) was the former EU laboratory procedure used to determine official fuel-consumption and CO2 values for cars and light commercial vehicles. It is now mainly relevant when reading older vehicle documents and historical emissions data, because WLTP replaced NEDC for modern type approval.
What Was the NEDC?
NEDC was a laboratory driving cycle used in the European regulatory framework to measure fuel consumption and exhaust-emission values under standardised conditions.
Its value was comparability: vehicles could be tested under the same controlled cycle. Its weakness was representativeness. Over time, the gap between NEDC laboratory values and typical real-world driving became too large for the procedure to remain the preferred modern benchmark.
Why Was NEDC Replaced?
The European Union introduced the Worldwide Harmonised Light Vehicles Test Procedure (WLTP) because it was designed to better reflect modern vehicles and more realistic driving conditions.
EU legislation began replacing NEDC with WLTP for new light-duty vehicle type approvals from 1 September 2017, with a transition period for older type approvals and CO2 monitoring. From 2021, manufacturer CO2 targets moved to WLTP-based values.
NEDC vs WLTP: What Changed?
| NEDC | WLTP | |
|---|---|---|
| Status | Historical/legacy procedure | Current modern EU light-duty test framework |
| Driving profile | Older, more simplified cycle | More dynamic speed and load patterns |
| Vehicle configuration | Less sensitive to equipment/configuration differences | More closely reflects mass, equipment and vehicle configuration |
| Typical official CO2 value | Usually lower | Often higher and more representative |
| Modern EU policy use | Legacy data and historical comparison | Current CO2 monitoring/type-approval basis |
There is no single universal conversion factor from NEDC to WLTP. During the transition, EU legislation used dedicated correlation methods because the relationship varies by vehicle.
Why Does NEDC Still Appear on Vehicle Documents?
Because millions of vehicles were type-approved and registered under the older regime. A used vehicle’s original Certificate of Conformity, technical database record or registration file may legitimately contain NEDC values.
During the regulatory transition, some vehicles also had both WLTP and correlated NEDC values recorded for different legal purposes. This is why two CO2 numbers on an older document do not automatically mean one is wrong.
NEDC, WLTP and Imported Vehicles
When registering an imported vehicle, the authority may need the emissions value that corresponds to the vehicle’s actual approval and production period. Substituting a modern WLTP figure for an older NEDC-approved vehicle, or vice versa, can distort tax and registration calculations.
A technical data sheet can help reconstruct the correct historical vehicle specifications when the original paperwork is incomplete, but the source and test basis of each emissions value should be identified clearly.
NEDC FAQ
Is NEDC still used for new EU cars?
Not as the modern type-approval procedure for new light-duty vehicles. WLTP replaced NEDC through the EU transition that began in 2017.
Why does my COC show NEDC values?
Your vehicle may have been approved during the NEDC era or during the NEDC/WLTP transition, when correlated values were still recorded for specific regulatory purposes.
Can I convert NEDC to WLTP with one formula?
No. EU transition rules used vehicle-specific correlation methods; there is no reliable universal multiplier.
Which CO2 value should be used for registration tax?
That depends on the destination country’s law and the vehicle’s approval data. Use the value required by the competent authority for that exact VIN and registration case.
