Square Inches to Tsubo (in² to tsubo)

1 square inch equals 0.0001951609 tsubo exactly.

1 square inch = 0.0001951609 tsubo

How to convert square inches to tsubo

To convert square inches to tsubo, multiply the number of square inches by 0.0001951609. This factor is exact. To go the other way, multiply tsubo by 5,123.97719 (rounded).

tsubo = square inches × 0.0001951609

Example: 10 square inches = 0.001951609 tsubo.

About these units

Square Inch (in²)

US & ImperialCurrent unit

A square one inch on a side, exactly 6.4516 cm². Used for small parts and for pressure (pounds per square inch).

Latin uncia, one twelfth, gave English the inch, which Old English borrowed as ynce. A statute of Edward II in 1324 defined it as three barleycorns, dry and round, set end to end, and the barleycorn remained the base for centuries after 1066. The modern square inch rests on a 20th-century agreement: the United States adopted a yard of exactly 0.9144 meter on 1 July 1959, the United Kingdom followed effective 1 January 1964, and the inch became exactly 25.4 mm.

Squaring that gives exactly 6.4516 cm² for one square inch, and one square meter is about 1,550 of them. Its best-known descendant is the pound per square inch, psi, the pressure unit still used for American tires and air tanks: atmospheric pressure at sea level is about 14.7 psi, a car tire is typically inflated to around 32 psi above the surrounding air, and one psi is about 6.895 kilopascals. The square inch itself is common in the US and UK for small parts and printed material.

1 square inch = 0.00064516 square meters (exactly).

Sources: Wikipedia: Square inch; Wikipedia: Inch; Wikipedia: Pounds per square inch

Tsubo (tsubo)

JapaneseTraditional unit (still used in some regions)

Exactly 400/121 m² (3.3058 m²), one square ken: about two tatami mats. Still the usual unit for land and property prices in Japan.

Walk into a Japanese estate agent's window and the land is still priced per tsubo. The unit is the area of a square ken, which is six shaku on a side, so 36 square shaku. Once the shaku was fixed at 10/33 metre, the tsubo followed as exactly 400/121 square metres, about 3.306.

Builders think of it as two tatami mats, since a mat is half a tsubo, and some sources also count it as 10 go. In farming contexts the same area is sometimes called a bu. A tsubo is a very small plot, so larger land is quoted in multiples such as the se, tan and cho.

The unit travelled with Japanese rule. Korea's pyeong and Taiwan's ping are the same 3.3058 square metres. South Korea formally banned the pyeong in 1961 and made commercial use an offence in 2007, yet it persists informally, much as Japan kept the tsubo after metric units became the legal standard.

1 tsubo = 3.305785124 square meters (approximately).

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

Related conversions

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