Thailand Area Formats
Thailand uses several area measurements that are uncommon in the rest of the world.
These are most commonly seen in regard to real estate, measuring land and house sizes.
Rai is the largest unit of land size commonly used and is equal to 1600mm2, or a square of 40 meters by 40 meters.
One Ngan is 400m2, or a square of 20 meters by 20 meters. There are 4 Ngan per Rai.
Tarang Wah ตารางวา
Wah is commonly used for house sizes, or for the remainder units of land sizes after the Whole Rai.
One Wah is 4m2, or a square of 2 meters by 2 meters. There are 100 Wah per Ngan and 400 Wah per Rai.
Thailand Land Size & Area Converter
Use the tool below to easily convert between Rai, SqM, Acres, Hectares etc.
Background to Thailand Area Measurements
For thousands of years the traditional Thai measurement system of Rai, Ngan, and Tarang Wah were used to quantify and assess land sizes, room sizes etc. It wasn't until 1923 that a Thai law introduced the modern metric system that we know of today.
However, the old traditional system is still widely used throughout the country in various institutions such as Land Offices, Architects, Land Surveyors and the like.
To give clarity of what each of the traditional measurements equate to in the metric system we start with the “Rai” which is equivalent to 1600 square metres. From there we can easily calculate the remaining measurements.
There are 4 “Ngan” in a Rai, therefore, one Ngan equals 400 square metres. Finally, the “Tarang Wah”...we see that there are 100 Tarang Wah per Ngan and 400 Tarang Wah per Rai. So, one Tarang Wah is equivalent to 4 square metres.
As with land, signs advertising rooms, condominiums etc can also be found using the Thai measuring system. Typically, the size in square Ngan is used.
Finally, multi storey properties are frequently advertised with a sign displaying the land size or footprint of the property in square Ngan as opposed to the total living area.
It is desirable for a foreigner who is interested in purchasing or leasing land in Thailand to be knowledgeable of these traditional measuring systems as it is unusual for officialdom to convert traditional measurements into the modern metric system.
Typically, when a purchaser or seller attends the Land Office to conduct land sales or purchases, all documentation will be presented not only in the traditional Thai measuring system, but he/she will also be confronted with the traditional Thai numbering system which is of Sanskrit heritage and of no roman characters.
To add to the difficulty, it is also common in the more rural parts of Thailand to see signs where the “land for sale” sign is in Thai language using the Sanskrit numbers, making it virtually impossible for the non Thai speaker to gain any understanding of what is being offered.
It is important to be aware of certain regulations when purchasing or leasing land in Thailand. Firstly, all land has a minimum sale value regardless of the price agreed upon by the buyer or seller. This means that each Rai, Ngan and Wah will have a fixed amount of tax duty duly payable on completion of any transaction and this taxable amount will be based on the Thai measuring system, not the Metric System. This land valuation is decided by each of the land offices independently in each of the 76 provinces.
The Land Office tax valuations are not applicable to property, specifically houses which are built on the land to be purchased/leased etc. Thereby meaning that a foreigner who cannot own land in Thailand, can still purchase a house on a piece of land and will not be liable to any tax payable as he is only purchasing the house and the land remains the property of the Thai land owner.