What are the land measurements in Thailand?

Thai Measurements:
1 Wah  = 4 Square Meters
1 Ngan = 100 Wah = 400 Square Meters
4 Ngan = 1 Rai = 1600 Square Meters

Western Standards:
2.50 Rai = 1 Acre
6.25 Rai = 1 Hectare