Expatistan's Cost of Living Index

[PaulB]

Expatistan (no affiliation) is a database of costs of living in different cities.

This is their Cost of Living Index comparing 138 cities, and here are the ones in East Asia and Southeast Asia:

1. Tokyo (Japan) 304
2. Singapore (Singapore) 222
3. Hong Kong (Hong Kong) 216
4. Shanghai (China) 137
5. Seoul (South Korea) 124
6. Beijing (China) 116
7. Kuala Lumpur (Malaysia) 116
8. Jakarta (Indonesia) 115
9. Bangkok (Thailand) 112
10. Manila (Philippines) 103

To calculate each cities' Cost of Living Index value, we start by assigning a value of 100 to a central reference city (that happens to be Prague). Once the reference point has been stablished, the Price Index value of every other city in the database is calculated by comparing their cost of living to the cost of living in Prague.
Therefore, if a city has a Price Index of 134, that means that living there is 34% more expensive than living in Prague.

How accurate would you guys say this Index is?