Thailand is approximately 513,120 sq km, while Cambodia is approximately 181,035 sq km, making Cambodia 35.28% the size of Thailand. Meanwhile, the population of Thailand is ~69.0 million people (52.1 million fewer people live in Cambodia).
This to-scale map shows a size comparison of Thailand compared to Cambodia. For more details, see an in-depth quality of life comparison of Cambodia vs. Thailand using our country comparison tool.