I would like to express my thanks to my wife for giving me the idea to build this page, to my Thai and Thai resident friends for their valuable assistance and feedback. Additional information is referenced at the bottom of the page.
In 1923 Thailand went metric even today some traditional units remain in common use. Area measurements are in use today as are some length measurements used in construction. The odd volume or weight unit are popular in pharmacies and farming communities.
Length
Cadastral plans use a scale of 1:4,000 (1 centimetre when plotted on paper equals one sen which is 40 metres or 4,000 centimetres).
Anthropic meanings of some length measurements are:
- Krabiat - Quarter of a finger
- Nio - Finger
- Khuep - Span
- Sawk - Cubit (middle finger to elbow)
- Wah - Outstretched arms
| Metric | Thai | ||||||
|---|---|---|---|---|---|---|---|
| Centimetre Metre Kilometre |
Krabiat | Nio | Khuep | Sawk | Wah | Sen | Yoht |
| 0.521 cm | 1 | - | - | - | - | - | - |
| 2.083 cm | 4 | 1 | - | - | - | - | - |
| 25 cm | 48 | 12 | 1 | - | - | - | - |
| 50 cm | 96 | 24 | 2 | 1 | - | - | - |
| 2 m | 384 | 100 | 8 | 4 | 1 | - | - |
| 40 m | 7,680 | 1,920 | 160 | 80 | 20 | 1 | - |
| 16 km | - | - | - | 32,000 | 8,000 | 400 | 1 |
Usage: For calculations select the desired unit and enter the desired quantity.
Tip: To keep a history of your measurements use notes, if your browser has local storage enabled they will be available when you visit next time.
Area
Official documents relating to land express size in three main units of area. This can cause confusion. Requiring the use of google especially for foreigners residing in Thailand. Documents show a column layout expressed as rai, ngan, and tarang wah with numbers or fractions in the corresponding column below.
| Rai | Ngan | Tarang wah |
| 0 | 0 | 21 |
This would be equal to 85.20 square meters.
Anthropic meaning:
- Tarang wah - Squared (outstretched arms)
| Metric | Thai | ||
|---|---|---|---|
| Square metre | Tarang Wah | Ngan | Rai |
| 4 m² | 1 | 0.01 | 0.0025 |
| 400 m² | 100 | 1 | 0.25 |
| 1600 m² | 400 | 4 | 1 |
Note: To approximately express an acre (4,046.86 m²) in Thai "two rai two ngan and eleven tarang wah ".
Weights
Salueng and baht are still commonly used today in purchasing herbal medicines and gold. Other weights are not as common and often metric is used, occasionally in combination with traditional units.
| Metric | Thai | ||||
|---|---|---|---|---|---|
| Grams Kilograms |
Salueng | Baht | Tamlung | Chang | Haap |
| 3.75 g | 1 | - | - | - | - |
| 15 g | 4 | 1 | - | - | - |
| 60 g | 16 | 4 | 1 | - | - |
| 1200 g (1.2 kg) | 320 | 80 | 20 | 1 | - |
| 60,000 g (60 kg) | 16,000 | 4,000 | 1000 | 50 | 1 |
Note: Gold baht weight differs from 15g to 15.16g
Volume
Volumes still in use by farmers include thang (bucket) and kwian (oxcart used for the transportation of grain or rice).
| Metric | Thai | ||||
|---|---|---|---|---|---|
| Litres Cubic metres |
Thanan | Thang | Sat | Ban | Kwian |
| 1 l | 1 | - | - | - | - |
| 20 l | 20 | 1 | - | - | - |
| 25 l | 25 | 1.25 | 1 | - | - |
| 1,000 l (1 m³) | 1,000 | 50 | 40 | 1 | - |
| 2,000 l (2 m³) | 2,000 | 100 | 80 | 2 | 1 |