Convert Rai to Square Millimeter (raimm²)

The rai is the traditional Thai land unit, equal to 1,600 square meters, used in real estate and agriculture.

1,600,000,000
1 rai1,600,000,000 mm²NIST · BIPM accuracy

Rai to Square Millimeter Conversion Table

10 common values
RaiSquare Millimeter
1 rai1,600,000,000 mm²
5 rai8,000,000,000 mm²
10 rai16,000,000,000 mm²
50 rai80,000,000,000 mm²
100 rai160,000,000,000 mm²
500 rai800,000,000,000 mm²
1,000 rai1,600,000,000,000 mm²
5,000 rai8,000,000,000,000 mm²
10,000 rai16,000,000,000,000 mm²
50,000 rai80,000,000,000,000 mm²

How to Convert Rai to Square Millimeter Manually

Step by Step

Converting rais to square millimeters is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

  1. 1
    Take your value in rais
    Start with the number of rais (rai) you want to convert.
  2. 2
    Multiply by 1,600,000,000
    The conversion factor from rai to mm² is 1,600,000,000. Multiply your value by this number.
  3. 3
    Read the result in square millimeters
    The result is your value in square millimeters (mm²).
Practical Examples
1 rai
equals
1,600,000,000 mm²
5 rai
equals
8,000,000,000 mm²
10 rai
equals
16,000,000,000 mm²
25 rai
equals
40,000,000,000 mm²
100 rai
equals
160,000,000,000 mm²

Formula

Multiply the value in rais by 1,600,000,000. For the reverse direction, multiply by 6.25 × 10^-10.

Forwardmm² = rai × 1,600,000,000
Reverserai = mm² × 6.25 × 10^-10
Example: 10 rai × 1,600,000,000 = 16,000,000,000 mm²

Tips

Use these in everyday conversions
  • 1 rai = 1600 m² = 0.16 ha.
  • 1 rai = 4 ngan = 400 tarang wa.
  • 1 hectare = 6.25 rai.

Common Mistakes

Avoid these
  • Assuming rai equals hectare — only 16%.
  • Mixing rai with ngan or tarang wa without conversion.
  • Using rai outside Thailand — not internationally recognised.

About Rai and Square Millimeter

What is the Rai?

The rai equals exactly 1,600 square meters (40 m × 40 m) and is the traditional Thai land unit, still officially used in Thailand for real estate, agriculture, and property records. The rai is divided into 4 ngan (each 400 m²), and 1 ngan equals 100 wa (each 4 m²). Despite Thailand's adoption of the metric system, the rai remains the everyday unit for buying and selling land in Thai contexts — a small urban plot might be 1 rai, while rural farms are quoted in tens or hundreds of rai. The rai relates to the square meter (1 rai = 1,600 m²), the hectare (1 ha = 6.25 rai), and the acre (1 acre ≈ 2.529 rai). The rai's exact metric definition (1,600 m²) makes conversion to SI units precise, unlike many traditional land units.

  • Thai rural property and farmland
  • Thai real-estate listings
  • Agricultural yield reporting in Thailand
Real-world examples

A small Thai farm might be 10–20 rai (1.6–3.2 ha). Thai rice yields: 400–600 kg per rai.

What is the Square Millimeter?

The square millimeter equals one millionth of a square meter (10⁻⁶ m²) and is the precision area unit for electronics, microfabrication, mechanical engineering, and component cross-sections. Wire gauges in electronics specify cross-sectional area in mm² (a 2.5 mm² wire is standard for household lighting circuits). Computer chip die sizes and printed circuit board footprints are measured in mm². The square millimeter relates to the square centimeter (100 mm² = 1 cm²), the square meter (1,000,000 mm² = 1 m²), and the square inch (1 mm² ≈ 0.00155 in²). Engineering tolerances, microscope-image areas, and laser-spot sizes all use this scale. The square millimeter is critical in stress calculations: pressure (N/mm²) and strength (MPa) calculations in mechanical engineering routinely use this unit.

  • Electrical cable cross-section (e.g. 2.5 mm² copper)
  • Microelectronics and semiconductor areas
  • Pharmaceutical tablet surface areas
Real-world examples

Typical household wiring is 2.5 mm² copper. A grain of rice covers about 10 mm². A pin head is under 1 mm².

Learn About Both Units

🗺️ Reference

What is the Rai?

Read the unit page →
🗺️ Reference

What is the Square Millimeter?

Read the unit page →

Rai to Square Millimeter FAQ

5 questions
How many square millimeters in a rai?
One rai equals 1,600,000,000 square millimeters.
How do I convert rais to square millimeters?
Multiply the rai value by 1,600,000,000 to get the equivalent in square millimeters.
What is 100 rais in square millimeters?
100 rais equals 160,000,000,000 square millimeters.
Is a rai bigger than a square millimeter?
Yes. 1 rai equals 1,600,000,000 square millimeters, so one rai is larger.
How to convert rais to square millimeters without a calculator?
Multiply by 1,600,000,000 for a quick estimate; use a calculator for precise results.

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