Convert Mu (亩) to square feet

A traditional unit rebuilt on the metre

The mu is ancient, but the value in use today is a twentieth-century construction. When China adopted the market system of weights and measures, the mu was redefined so that fifteen mu make exactly one hectare, giving 666.6667 m². Six hundred mu make one qing, the unit used for large estates and, historically, for state landholdings.

That redefinition is why Chinese agricultural statistics convert cleanly: the mu is not an approximation of an older field size but a metric fraction wearing a traditional name. Pre-1930 documents may intend a different, locally variable mu, and historical research should not assume the modern figure.

Why the mu dominates Chinese data

Household contracted farmland, grain yields, subsidy rates and land-transfer prices are all reported per mu. Yield figures such as "600 kg per mu" are the standard way Chinese agronomy communicates, and converting them to tonnes per hectare — multiply by 0.015 to get tonnes, or by 15 to move per-mu to per-hectare — is the first step in comparing Chinese data with FAO or USDA series.

Because the average rural household holds only a few mu, the unit is also the natural granularity of policy: land-transfer contracts, homestead allocations and compensation for requisitioned farmland are all denominated in mu, not hectares.

Mu outside mainland China

Taiwan uses the Japanese-derived kah and the tsubo rather than the mu, and Hong Kong land is dealt with in square feet. Overseas Chinese agricultural communities in Southeast Asia may use a mu descended from pre-standardisation practice, which can differ materially from 666.67 m².

The safe rule is that "mu" in any post-1950 mainland source is the standard market mu, and "mu" anywhere else needs a stated value. Republican-era and imperial sources are the ones most likely to mislead a modern reader, because the word is identical and the area is not.

Converting per-mu quantities correctly

Per-area rates invert: a rate per mu becomes a rate per hectare by multiplying by fifteen, not dividing. Getting the direction wrong turns a plausible Chinese yield into an implausible one, and the error survives review because both numbers look like agriculture.

For compensation and valuation work, note that the mu figure in a contract usually refers to contracted area rather than surveyed area, and rural contracted areas in China have historically been understated relative to survey. The conversion is exact; the input may not be.

Chinese land statistics and the mu

The mu is exactly 666.67 square metres — one fifteenth of a hectare — and it is the unit Chinese agricultural policy is written in. Grain yields, subsidy thresholds, contracted-land areas and the national arable-land red line are all expressed in mu, so any work with Chinese agricultural data means working with the unit rather than converting away from it.

The awkward metric value follows from the mu having been standardised against the historical bu rather than designed around the hectare. Because fifteen mu make a hectare exactly, yields per mu multiply cleanly to yields per hectare, and that is the safest conversion route for statistics: convert the area denominator once at the end rather than converting each yield figure.

Common mistakes to avoid

• Fifteen mu make one hectare — to convert a per-mu rate to per-hectare, multiply by 15 rather than divide.
• Pre-standardisation and overseas mu can differ substantially from the modern 666.67 m².
• Contracted mu in rural contracts is not always the surveyed area; treat it as a contractual figure.

Questions people ask about the Mu (亩)

How many square metres is one Chinese mu?

Exactly 666⅔ m² (666.6667 m²), because fifteen mu were defined to make one hectare under the Chinese market system of units.

How do I convert a yield of kg per mu to tonnes per hectare?

Multiply kilograms per mu by fifteen to get kilograms per hectare, then divide by 1,000. So 600 kg per mu is 9 tonnes per hectare.

Is the mu still official in China?

Yes. It remains in lawful use for land alongside the metric system, and Chinese agricultural statistics, subsidies and land contracts are routinely denominated in mu.