Direct answer: Japan's kei class limits engine displacement to under 660cc and caps external size at 3.4 m long, 1.48 m wide and under 2.0 m high. These limits have applied since 1 October 1998. They shape what kei cars can be, and they are the reason kei cars are small, light and cheap to run.
What are the current kei limits?
- Engine displacement: under 660cc
- Maximum length: 3.4 m
- Maximum width: 1.48 m
- Maximum height: under 2.0 m
Source: summary of the kei class as published on Wikipedia (Kei car). [HELD: confirm these values against the official MLIT or equivalent Japanese government source before treating them as definitive.]
Why did the limits change?
The class has been revised several times since it was created in 1949. The 1998 revision is the one most often cited today, and it is the basis for the figures above. Older kei cars may have been built to earlier limits, so check the model and year.
What do the limits mean in practice?
- Small engines keep fuel use and tax low.
- Short, narrow bodies suit tight city parking.
- Limited width and weight reduce highway stability and passenger room.
- Some models have turbochargers, which add power within the limit.
Do export versions follow the same limits?
Not necessarily. Some export versions differ from the Japanese original in width, power or equipment. Check the specific model's dimensions and specification before you assume the Japanese limits apply.
Related guides
FAQ
What is the engine limit for a kei car?
Under 660cc.
Are the limits the same as in 1949?
No. The class has been revised, and the 1998 limits are the current ones cited here.
Do kei limits apply abroad?
No. Other countries set their own size and safety rules.
Last reviewed: 2026-10-20. Author: [AUTHOR NAME AND CREDENTIAL LINE - NOT SUPPLIED].
Dimensions are published as a summary and are being confirmed against the official Japanese source. Import and registration rules vary by country. Confirm with your national registry or customs authority before you buy.
