Se to Square Kilometers (se to km²)

1 se equals 0.00009917355372 square kilometers (rounded).

1 se = 0.00009917355372 square kilometers

How to convert se to square kilometers

To convert se to square kilometers, multiply the number of se by 0.00009917355372. The factor is rounded to 10 significant digits. To go the other way, multiply square kilometers by 10,083.33333 (rounded).

square kilometers = se × 0.00009917355372

Example: 10 se = 0.0009917355372 square kilometers.

About these units

Se (se)

JapaneseTraditional unit (still used in some regions)

30 tsubo, about 99.17 m².

Between the humble tsubo and the field-sized tan sits the se, a plot of 30 tsubo. In square metres that is exactly 12,000/121, or about 99.17, which is just under one are, the metric land unit of 100 square metres. A se measures roughly ten metres by ten, a small garden or a slice of a paddy.

The scale is decimal above this point. Ten se make one tan, and a hundred se make one cho, so the se works as the first step in the farmland ladder rather than a unit with a life of its own. Property listings today seldom use it, and it is mostly met in old land records and in conversion tables.

Its exact size comes from the Meiji legal definition. The 1891 law set the shaku at 10/33 metre, and the tsubo as the square of six shaku, so every larger land unit built on the tsubo inherited a fixed metric value. Before that, the shaku itself varied by era and use.

1 se = 99.17355372 square meters (approximately).

Sources: Wikipedia: Japanese units of measurement; Wikipedia: Shaku (unit); Wikipedia: Tsubo

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.