📐 Area Unit Converter
How It Works
Enter a value in any field for instant conversion across metric, imperial, and East Asian land units. Key relationships: 1 hectare = 10,000 m² ≈ 2.47 acres; 1 acre ≈ 4,047 m²; 1 ping ≈ 3.306 m²; 1 square foot ≈ 0.0929 m².
A Field Guide to East Asian Land Units
Property listings and land records across East Asia use units you won't find in Western textbooks:
| Unit | Size | Where & what for |
|---|---|---|
| Ping（坪） | 3.306 m² — a 6×6 shaku square, i.e. two tatami mats | Taiwan & Japan apartments; every Taiwanese listing quotes ping |
| Jia（甲） | ≈ 9,700 m² ≈ 0.97 ha | Taiwan farmland, from the Dutch colonial era |
| Fen（分） | 1/10 jia ≈ 294 m² | Taiwan farmland subdivisions |
| Mu（畝） | ≈ 666.67 m²; 15 mu = 1 ha | Mainland China agriculture and land policy |
Handy anchor: a Taiwanese "30-ping apartment" is about 99 m² ≈ 1,067 sq ft — but note that Taiwanese registered areas usually include a share of common facilities (often 30–35%), so the interior is smaller than the headline number.
Getting a Feel for Acres and Hectares
- An acre was medieval England's "one ox-team, one day" of plowing — 43,560 sq ft, about 60% of a soccer pitch. An American football field including end zones is 1.32 acres.
- A hectare is a clean 100 m × 100 m square — about 1.4 soccer pitches, or 2.47 acres.
- Square feet vs square meters: divide sq ft by ~10.8 to get m². A US "2,000 sq ft house" ≈ 186 m².
- Scaling trap: area grows with the square of length — doubling a room's side quadruples its area. A "20% longer" plot is 44% larger if both sides scale.
Frequently Asked Questions
How do countries differ in quoting apartment sizes?
The US quotes interior square feet; most of Europe quotes usable square meters; Taiwan and Japan quote ping (Taiwan's registered ping usually bundles common areas; Japan's 専有面積 excludes them). Comparing across markets, always ask what the number includes.
What is an "are"?
100 m² — the base of the hectare (hecto-are = 100 ares). Rare on its own today, but it survives in continental European land registries.
Why does 1 km² equal 100 hectares and not 1,000?
Because area scales with the square: 1 km = 1,000 m, so 1 km² = 1,000² m² = 1,000,000 m² = 100 ha. Squared units are the classic place mental math goes wrong.
How precise are the conversions?
Six decimal places with standard factors (1 ping = 400/121 m² exactly, 1 acre = 4,046.8564224 m²). More than enough for listings and land records.