Area quantifies two-dimensional surface. The square metre (m²) is the SI unit for area; roughly the size of a single parking space. For land measurement, hectares (100 m × 100 m = 10,000 m²) are the standard worldwide in agriculture and real estate outside the US and UK. Countries report their land areas in square kilometres (km²), while flooring and construction materials are quoted in m² or ft².
The acre (4,047 m²) originated as the area a yoke of oxen could plough in one day — a practical agricultural unit that persists in the US and UK land markets. One square mile equals exactly 640 acres. A standard association football pitch is approximately 0.7 hectares (7,140 m²), giving a useful mental benchmark for large areas.
| 1 acre | = 4,046.86 m² |
| 1 hectare | = 2.47105 acres |
| 1 km² | = 100 ha |
| 1 ft² | = 0.0929 m² |
| 1 mi² | = 2.58999 km² |
| 1 ha | = 10,000 m² |