Ngan (Thai) to Square Kilometers (ngan to km²)

1 ngan (Thai) equals 0.0004 square kilometers exactly.

1 ngan (Thai) = 0.0004 square kilometers

How to convert ngan (Thai) to square kilometers

To convert ngan (Thai) to square kilometers, multiply the number of ngan (Thai) by 0.0004. This factor is exact. To go the other way, multiply square kilometers by 2,500.

square kilometers = ngan (Thai) × 0.0004

Example: 10 ngan (Thai) = 0.004 square kilometers.

About these units

Ngan (Thai) (ngan)

ThaiTraditional unit (still used in some regions)

A quarter of a rai: exactly 400 m². Used for house plots in Thailand.

Ngan means work in Thai, and as a land unit it is the middle step between the rai and the square wa. Four ngan make one rai, and one ngan holds 100 square wa, so it covers 400 square meters, the area of a square 20 meters on a side.

That size suits a village or suburban house plot, which is why ngan crop up in listings for building land, while farms are quoted in rai. Deeds combine the units, so a title might read as a number of rai, then ngan, then square wa.

The ngan comes from the same traditional Thai scheme as the wa and sen, fixed against metric lengths after the cadastral survey of 1896. Its 400 square meters are exact in the modern definition, and it is about one tenth of an acre.

1 ngan (Thai) = 400 square meters (exactly).

Sources: Wikipedia: Rai (unit); Wikipedia: Thai units of measurement

Square Kilometer (km²)

Metric (SI)Current unit

One million square meters (100 hectares). Used for the area of cities, countries and lakes.

Metric land measure took a surprisingly long time to settle on the kilometer. The meter was defined in 1799, yet people initially preferred the myriameter, 10,000 meters, and the French phrase myriamètres par heure was still in print in 1802. The Netherlands adopted the kilometer in 1817 under the name mijl. Once the kilometer was established, the square kilometer followed naturally as the unit for areas too large to count comfortably in hectares or square meters.

One square kilometer is 1,000,000 square meters, or 100 hectares, about 0.3861 square miles or 247.1 acres. A useful picture comes from history: many medieval European cities were enclosed by walls around roughly a square kilometer, with Delft at about 0.9 km² and Lucca at about 1.09 km². A standard 18-hole golf course of 6,000 meters needs about 0.8 km². The symbol km² means the square of a kilometer, not a thousand square meters. The planned Square Kilometre Array radio telescope takes its name from the collecting area it aims for.

1 square kilometer = 1,000,000 square meters (exactly).

Sources: Wikipedia: Square kilometre; Wikipedia: Kilometres per hour

Related conversions

See all area units.