The common units of LandMeasurement in Thailand are Rai, Ngan, Talang Wah (Square Wah) & Talang Mett (Square Metre). Land prices are usually expressed in baht per Rai and baht per Ngan or Tarlng Wah (for smaller plots under 1 Rai). However, most foreign real estate agents list the land size in square meters (Sq.m or m2) for standard house, villa or condominium properties.

For building floor area or house area (under roof), the area size is usually expressed in square meters (Sqm or m2).
1 Rai = 4 Ngan (or 400 Talang Wah or 1600 Sqm.)
1 Ngan = 100 Talang Wah (or 400 Sqm.)
1 Talang Wah = 4 Sqm.
1 Talang Mett = 1 Sqm.

Conversions:

1 Acre = 2.5 Rai (approx.)
1 Hectare = 6.25 Rai (approx.)

Please note: Most title deeds in Thailand do not indicate the land size in numerical digits. The numeric measurement is indicated thus (#Rai – #Ngan – # Talang Wah & #/10). The size is indicated in Thai numerals so unless you can read or translate Thai numerals into Arabic numerals, please ask someone to translate the land size into Arabic numerals and units. Also, the same applies to the title deed number. You could also try converting yourself using the table below.