Area Unit Converter

Area Conversion: Acres, Hectares, Mu, and Why Area Scales as a Square

Base relationships of land units

Handy anchors: 1 hectare = 15 mu, 1 km² = 1500 mu, 1 mu ≈ 667 m². Memorize those three and you can estimate quickly in agriculture and real estate.

The mu value looks non-round (666.67) because it comes from the traditional "60 square zhang" definition, and since 1 zhang = 10/3 m, the result carries a repeating decimal. Do not multiply large datasets by 667 when reversing "how many mu is this area" — keep enough decimals, or the error compounds into a meaningful figure across a large plot.

What an acre looks like

The acre traces back to "how much a yoke of oxen could plow in a day", so it is not a tidy square number. Visual anchor: one acre is slightly smaller than a standard soccer field (a full pitch with surround is about 7,000 m²; the acre is about 4,047 m², so a pitch is roughly 1.7 acres).

Other common links: 1 square mile = 640 acres, and 1 acre ≈ 0.4047 hectare. US real estate and farmland trade heavily in acres.

Three different "area" readings

This is the biggest source of real-estate confusion — one apartment can report three areas:

These can differ by 20%–30%. When comparing prices per square meter, use the same reading — a "cheap" unit may simply have a larger shared-space ratio. This is a semantic gap no unit converter can resolve: the number converts correctly while the meaning changes.

Conversion and calculation caveats

• Area converts as a square, not linearly. A length factor multiplies once; an area factor multiplies the square of the coefficient. Since 1 foot = 0.3048 m, then 1 square foot = 0.0929 m² — that is 0.3048², not 0.3048. This squaring is the top cause of area-conversion errors.
• Compute the area first, then convert for irregular shapes; reversing the order injects needless intermediate rounding.
• Slope parcels. A hillside's true surface area exceeds its map projection; cadastral and agricultural surveys treat these as different numbers.
• The "ping" (坪) by region. Taiwan and Japan use ping (1 ping ≈ 3.3058 m²); Korea has a similar traditional unit. Resolve ping against its region.
• Mixed-unit drawings. Old plans may label "meters" but dimension in "chi", or mix both on one sheet. Verify before construction — such errors are expensive.

The tool covers square meter, square kilometer, hectare, mu, square centimeter, square millimeter, square mile, acre, square yard, square foot, square inch, and ping — all converted locally in the browser.