When you read specifications for EVs, one of the first things that grabs attention is the claimed range. That number can be quite different depending on the testing standard used. In Europe, the standard is known as WLTP, the Worldwide Harmonised Light Vehicles Test Procedure, while in China the standard is CLTC, the China Light-Duty Vehicle Test Cycle. These standards are laboratory test procedures aimed at producing comparable figures for energy use, emissions, or in the case of EVs, range on a single charge. While both are more reliable than many older testing cycles, they differ significantly in content, strictness, and how representative they are of real driving conditions.
Table of Contents
- How WLTP Testing Is Performed and Who Is Responsible
- What CLTC Is and How It Differs
- Side-by-Side Comparison: WLTP vs CLTC
- How to Estimate Your Real-World EV Range from WLTP or CLTC
- Frequently Asked Questions
- Final Thoughts
How WLTP Testing Is Performed and Who Is Responsible
WLTP was introduced to replace the older NEDC standard, with the goal of producing more realistic and harmonised data across countries. Under WLTP, type-approval tests are carried out by accredited independent testing bodies in certified laboratories. Automakers are not allowed to declare range figures under WLTP without validation by these independent authorities.
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Tests are conducted on vehicles placed on chassis dynamometers (rollers) in precisely controlled laboratory conditions. Factors like temperature, vehicle mass including optional equipment, tyre type and pressure, ambient conditions, and driving cycle phases (low, medium, high, extra-high speed) are strictly defined. Tests also include the effect of optional features, so what might otherwise be seen as “extra weight or drag” is included. Europe relies on its member states’ type approval authorities and independent labs to enforce these criteria.
One example of such a facility is the Vehicle Emissions Laboratories (VELA) in Ispra, Italy, part of the European Commission’s Joint Research Centre. VELA is independent of vehicle manufacturers and accredited under ISO/IEC 17020. It is one of the labs used to conduct emissions and energy consumption testing under EU regulations.
Other accredited labs include TÜV SÜD facilities, which are certified to perform WLTP and Real Driving Emissions (RDE) tests. TÜV SÜD ensures compliance for automakers seeking type approval and advertises its WLTP labs as state-of-the-art.
Since 2019 in the EU, all new passenger cars must comply with WLTP for type approval. Advertised ranges must match WLTP figures or risk non-compliance.
What CLTC Is and How It Differs
In China, CLTC is part of the national standard GB/T 38146.1-2019, developed by the China Automotive Technology & Research Center (CATARC). It was designed to reflect typical Chinese driving conditions, which often involve lower speeds and more urban traffic than in Europe.
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CLTC testing is also performed on chassis dynamometers, but the driving profile differs. Average speeds are lower, there are more stops and starts, and the test spends less time simulating highway driving. As a result, vehicles tested under CLTC typically achieve longer ranges on paper than when tested under WLTP. According to independent comparisons, CLTC values are generally 15 to 25 percent higher than WLTP for the same car.
Side-by-Side Comparison: WLTP vs CLTC
| Feature | WLTP (Europe) | CLTC (China) |
| Purpose and Origin | Harmonised European test to replace NEDC, designed for realism and stricter criteria | Developed by CATARC to reflect Chinese urban driving |
| Testing Authorities | Independent accredited labs, overseen by EU type-approval bodies | CATARC and government-approved labs under GB/T standards |
| Driving Profile | Mix of low, medium, high, and extra-high speed phases; max ~131 km/h; more highway driving | Slow, medium, and fast phases; max ~114 km/h; more urban stop-start |
| Strictness of Criteria | Considers optional equipment, mass variations, temperature, tyre type, aerodynamics | Stricter than old NEDC but less demanding than WLTP; weaker highway component |
| Real-World Accuracy | Tends to be closer to mixed real-world driving, though still optimistic | Often 15–25% higher than WLTP; overestimates long-distance range |
How to Estimate Your Real-World EV Range from WLTP or CLTC
Laboratory tests provide a useful benchmark, but actual driving rarely matches perfect lab conditions. Several independent sources highlight the gap between certified and real-world performance.
According to Gridserve, WLTP assumes mild weather and ideal conditions, so real-world figures are usually about 80–90% of the rated value. Green.Car suggests a “rule of thumb” of up to 20% less than WLTP in everyday conditions, and the ICCT reported an average 14% gap between WLTP and actual EV energy use in Europe.
For CLTC, comparisons show that figures are typically 15–25% higher than WLTP for the same vehicle. This means that in real-world conditions outside China, especially at higher speeds, the gap can be even larger.
A simple way to adjust the advertised numbers is:
- From WLTP, subtract about 10 to 20 percent to estimate your daily achievable range. For instance, a car rated at 500 km WLTP may deliver 400–450 km in practice.
- From CLTC, subtract about 15 to 30 percent. A 700 km CLTC rating might realistically mean 490–595 km, which often aligns closely with the WLTP equivalent.
Temperature extremes, highway driving, and use of climate control can further reduce range, while gentle city driving in mild weather may get you closer to the official figure.
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Frequently Asked Questions
Why does WLTP give lower numbers than CLTC?
Because WLTP includes higher speeds and more demanding driving cycles, while CLTC reflects slower, city-focused conditions.
Who performs WLTP testing?
Independent accredited labs like the European Commission’s VELA in Italy or TÜV SÜD facilities, under oversight of EU type-approval authorities.
Which standard is used in Europe?
WLTP is mandatory for all new cars sold in Europe. CLTC only applies in China.
How much higher are CLTC values compared to WLTP?
Typically 15–25% higher for the same model, sometimes more depending on battery size and aerodynamics.
Final Thoughts
Understanding EV range standards is crucial when comparing models, especially between Europe and China. WLTP provides a stricter, more realistic baseline for European drivers, while CLTC is more optimistic and reflects slower, city-focused conditions. By applying simple adjustment factors, buyers can get a clearer idea of what to expect in everyday use.
