Thai land measurement: rai, ngan, and square wah
Thailand does not use imperial acres or metric hectares alone on title deeds. Land area is recorded in traditional units: rai, ngan, and square wah. The hierarchy is fixed: 1 rai = 4 ngan = 400 square wah. Every expat reviewing land listings or chanote deeds needs this framework.
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Rai is the largest traditional unit on most chanote title deeds.
Ngan sits between rai and square wah in the hierarchy.
Full breakdown: 1 rai = 4 ngan = 400 square wah.
Thailand uses rai-ngan-wah on land documents, not acres or hectares alone.
Thai land units explained
These units appear on chanote title deeds issued by the Department of Lands. Marketing materials may convert to square metres, but the legal record uses traditional Thai measurement.
| Unit | Description | Equivalent | Typical use |
|---|---|---|---|
| Rai (ไร่) | Largest common unit | 1 rai = 4 ngan = 400 sq wah | Agricultural plots, large residential land, resort sites |
| Ngan (งาน) | Quarter rai | 1 ngan = 100 sq wah = 0.25 rai | Mid-size house plots, small development parcels |
| Square wah (ตารางวา) | Smallest common unit | 1 sq wah = 1/400 rai | Urban house lots, townhouse land, precise chanote entries |
| Wah (วา) | Linear measure | 2 metres (length, not area) | Boundary descriptions, not area calculation |
The rai hierarchy step by step
Build from the smallest unit upward. This is how Land Office staff and surveyors calculate total plot area on title deeds.
Start with square wah
Title deeds and land listings often state area in square wah (ตารางวา). This is the base counting unit for land area.
Group into ngan
One hundred square wah equals one ngan. Four ngan make one full rai.
Express as rai
Large plots are quoted in rai for simplicity. A 2 rai plot equals 8 ngan or 800 square wah.
Read the chanote
The Department of Lands records area in Thai traditional units on chanote title deeds. Match listing claims to deed figures during due diligence.
When agents use rai vs square wah
Listing format often reflects marketing strategy rather than deed accuracy. Know what each format implies.
| Listing format | Typical property type |
|---|---|
| Square wah only | Urban townhouses, small Bangkok house plots, shophouse land |
| Ngan and sq wah | Suburban house plots under one rai |
| Full rai | Agricultural land, resort plots, large estate parcels |
| Rai-ngan-wah notation | Official chanote format. Most accurate for due diligence comparison. |
Reading area on title deeds
Five practical tips when comparing agent listings to chanote records during due diligence. Area mismatches are a common source of overpayment.
- Compare listing area to chanote area exactly. Agents sometimes round or combine adjacent parcels incorrectly.
- Fractional rai appears as rai plus ngan plus sq wah, for example 1-2-50 means 1 rai, 2 ngan, 50 sq wah.
- Urban townhouse plots may show only square wah. Rural agricultural land usually shows rai.
- Do not confuse linear wah (length) with square wah (area). They measure different dimensions.
- Metric conversions exist but deeds use traditional units. See our square metre conversion guide for cross-reference.
Listing vs deed: Never sign a land purchase agreement based on agent area claims alone. Your lawyer compares the chanote figure to a current survey. Shrunk or inflated listings create boundary disputes after transfer.
Common mistakes
Expat buyers and long-stay residents encounter these errors when reading rai and ngan on title deeds. Verify your facts with licensed counsel before signing or paying a deposit.
- Accepting agent land area quotes without matching chanote deed rai-ngan-wah notation
- Confusing linear wah with square wah when comparing urban house plot listings
- Assuming metric marketing materials override Land Department traditional unit records
- Paying deposit before lawyer confirms deed area matches survey and contract schedule
- Ignoring fractional rai notation such as 1-2-50 on title search reports
Frequently asked questions
General answers on Thai traditional land measurement for expat property buyers. This is orientation, not legal advice for your specific transaction.
Q:What is a rai in Thailand?
A rai is the largest traditional Thai land area unit. One rai equals four ngan or four hundred square wah. It appears on chanote title deeds and rural land listings.
Q:What is a ngan?
A ngan is one quarter of a rai, equal to one hundred square wah. It is commonly used for mid-size residential plots between small urban lots and large agricultural parcels.
Q:What is a square wah?
A square wah (ตารางวา) is the smallest standard area unit on Thai title deeds. Four hundred square wah equal one rai. Urban house plots are often measured in square wah alone.
Q:Does Thailand use metric or imperial land measurement?
Thai title deeds use the traditional rai-ngan-square wah system. Metric square metres appear in some marketing materials but official Land Department records use traditional units.
Q:How do I read 1-2-50 on a title deed?
That notation means 1 rai, 2 ngan, and 50 square wah. Convert each tier: 1 rai plus 2 ngan (200 sq wah) plus 50 sq wah equals 450 square wah total, or 1.125 rai.
Q:Why do land listings use different units?
Agents choose whichever unit makes the plot sound larger or simpler. Always verify against the chanote deed in its original rai-ngan-wah format during due diligence.
Q:Does this guide replace a property lawyer?
No. Area measurement disputes can affect price and boundary rights. Your lawyer confirms deed area matches survey and contract during title search.
Q:Where should I start reading?
Begin with our buying property overview, then the due diligence checklist, then contact a lawyer before paying any deposit.