Convert Acre to Rai (ac → rai)

Converting acres to rais 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 acres

   Start with the number of acres (ac) you want to convert.
2. 2
   Multiply by 2.529285

   The conversion factor from ac to rai is 2.529285. Multiply your value by this number.
3. 3
   Read the result in rais

   The result is your value in rais (rai).

Multiply the value in acres by 2.529285. For the reverse direction, multiply by 0.395369.

• ✓1 acre = 43,560 ft² = 0.4047 ha.
• ✓640 acres = 1 square mile — a "section" in US land survey.
• ✓An acre is 43,560 ft² — a useful number for US real-estate calculations.

• ✗Using "acre" in modern European property — use hectares or m² instead.
• ✗Assuming an acre is a specific shape — it is only an area (any shape).
• ✗Multiplying acres by 4000 m² — correct value is 4046.86.

What is the Acre?

The acre equals exactly 4,046.8564224 square meters (or 43,560 square feet) and is the standard unit for American and British farmland, real estate, and recreational property. The unit's origin is medieval: an acre was the area a yoke of oxen could plow in one day, traditionally a strip 1 furlong (660 ft) by 1 chain (66 ft). Despite metric adoption in many fields, the acre persists in property records throughout the US and UK. A standard American football field (excluding end zones) is about 1.32 acres. The largest US state, Alaska, contains about 365 million acres. The acre relates to the square foot (43,560 ft² = 1 acre), the hectare (1 ha ≈ 2.471 acres), the square mile (640 acres = 1 mi²), and the square meter (1 acre ≈ 4,047 m²). US farms average around 446 acres, and the average UK farm is about 215 acres.

• US farmland and ranches
• UK rural property and estates
• Canadian rural property (legal survey system)

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