EV AER Conversion : How to convert CLTC to EPA

To check the AER of EVs by different AER testing agencies, we suggest to use the EV AER conversion system from CLTC to EPA.

Since the AER (All-Electric Range) is measured by different certification agencies for each country, even for models with the same specifications, AER is different for each country. For those of you who is having trouble with estimating the AER of a model that is not released in US but in China, we introduce the EV AER conversion program that can convert the AER by different certification agencies.

EV AER Conversion (CLTC to EPA)

This AER converter is a system that convert the AER based on the database of already released EVs’ AER which were certified by the agencies, and is not a simple conversion from kilometers to miles, but a highly accurate system. Please refer to the procedure below for usage.

  1. Select the manufacturer of the EV you want to convert → “Select EV manufacturer”
  2. Enter the AER in CLTC that you want to convert to the EPA standard (in miles) → “Enter AER in CLTC (km)”
  3. Click the button “Convert!”
  4. Check the converted AER “US EPA AER”

EPA AER = 0 miles


Since the converted values are based on a database that is calculated for each brand, there may be some differences based on currently released vehicles, so please use it for the purpose of estimating the AER for models that is not released in certain country.
EX) BYD HAN launch AER in US 500 miles → China CLTC AER 000 km

What is CLTC and EPA?

These days, when driving a car that considers the environment and energy efficiency is becoming more important, the popularity of EVs is increasing. However, the criteria for measuring vehicle fuel economy are different between United States and China. The EPA(Environmental Protection Agency) is a national agency of the United States that evaluate the AER and fuel efficiency(MPGe) of EVs in miles. On the other hand, CLTC(China Light-duty Vehicle Test Cycle) a national agency of the China that evaluate the AER and fuel efficiency of EVs in kilometers. Therefore, there are situations in which it is difficult to easily compare the estimated range of EVs with US and Chinese standards.

What are the differences between the agencies?

There are difference between EPA and CLTC since there are differences in the conditions for measuring the AER for each agency (the same applies to other certification agencies). Because the condition is an element that is not disclosed to the public, it is not possible to do a comparative analysis of the difference exactly, but if there is a difference in basic conditions such as temperature conditions, for example, a slight difference in AER occurs.

Also, it is expected that there will be a difference in the testing cycles. For example, if one agency’s test cycle consists only of city driving, highway driving, or constant speed driving, another agency may repeat this driving condition several times or add other conditions to conduct the test. That is where the difference arises.

If you want to convert the AER by two agencies, it is meaningless to simply change the mile unit to kilometer, so you can estimate what the AER is by collecting the data of various types of vehicles that have been measured so far, such as the converter above. It is reflected in the converter so that it can be used, so I hope it helps to convert it to models that are released in the US but not yet released in China.

EV AER Database

As mentioned earlier, in order to set up the EV AER conversion system, the AER of EVs that have been released so far has been compiled and organized by certification agencies. There is also a method of converting the AER for each vehicle type based on the entire data, but after checking the data, it was confirmed that a similar level of difference occurs for each manufacturer. This is judged to be reflected at a similar level for the same vehicle model within the manufacturer that affects the AER even though the certification body is the same, and accordingly, the manufacturer of the vehicle to be converted is selected to increase accuracy.

Where the data came from?

The AER data was collected based on the test results disclosed to the public by each agency, and if not disclosed by the agency, it was organized according to the standards listed on the manufacturer’s official website for each trim of the vehicle model. Since there are some models with differences between the AER indicated by some certification agencies and official websites, the overall data consistency was improved by considering the AER results tested by actual users. However, it was difficult to organize the data because the trim (battery specifications, driving method, etc.) of vehicles sold by manufacturers in each country is different.


With a simple interface and easy-to-use functioned EV AER conversion, this site has established a system for converting AER from CLTC to EPA standard, which will provide convenience to users. If you want to convert between different certificate authorities, please refer to the link above.