What is a Square Kilometer?

The square kilometer equals 1,000,000 square meters (or 100 hectares) and is the international standard for measuring large areas: cities, national parks, lakes, watersheds, and country-level statistics. Population density is conventionally given in people per km² (e.g., Singapore has roughly 8,400 people/km², Mongolia has fewer than 2). The largest US national park, Wrangell-St. Elias in Alaska, covers about 53,000 km². France is 643,801 km², and the largest country, Russia, spans 17 million km². The square kilometer relates to the square meter (1 km² = 1,000,000 m²), the hectare (1 km² = 100 ha), the square mile (1 km² ≈ 0.386 mi²), and the acre (1 km² ≈ 247.1 acres). Geographic information systems, climate science, and regional planning all rely on square kilometers as the base unit for area.

Visual reference for how the square kilometer relates to other area units. Each row links to the full converter for that pair.

• Country and city geographic area reporting
• National-park and protected-area sizes
• Large-scale environmental studies (deforestation, etc.)

• ✓1 km² = 100 hectares = 1,000,000 m².
• ✓1 km² = 0.386 square miles.
• ✓Multiply km × km in metric to get km² — but always keep consistent units.

• ✗Mixing km² and km when comparing geography — 10 km is a length, 10 km² is an area.
• ✗Confusing km² with the square mile (mi²) in international comparisons.
• ✗Reading "million km²" as "km²" on continental-scale maps — factor of 10⁶.