Land in Thailand is measured in the standard unit of 1 Rai

1Rai = 4 Ngan = 1600 Square Meters
1 Ngan = 100 Talang Wah = 400 SqM
1 Talang Wah = 4 SqM

Common Western Conversions:

1 Acre = 2.5 Rai
1 Hectare = 6.25 Rai