Convert Hectare to Square Mile (ha → mi²)

Converting hectares to square miles is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in hectares

   Start with the number of hectares (ha) you want to convert.
2. 2
   Multiply by 0.003861

   The conversion factor from ha to mi² is 0.003861. Multiply your value by this number.
3. 3
   Read the result in square miles

   The result is your value in square miles (mi²).

Multiply the value in hectares by 0.003861. For the reverse direction, multiply by 258.99881.

• ✓1 ha = 10,000 m² = 100 m × 100 m.
• ✓1 ha ≈ 2.47 acres — quick check for US/UK comparison.
• ✓Agricultural yields quoted as tonnes/hectare are standard worldwide.

• ✗Using hectares for very small plots — m² is clearer.
• ✗Converting acres to hectares with 2.5 factor — correct is 2.47 (1.2% error).
• ✗Treating "a few hectares" as an exact figure in contracts — always specify.

What is the Hectare?

The hectare equals exactly 10,000 square meters (100 m × 100 m) and is the international standard area unit for agricultural land, forestry, and large land development. Adopted as part of the metric system in 1795, the hectare's name combines 'hect-' (one hundred) with 'are' (the basic metric land unit of 100 m²) — meaning 100 ares. A standard FIFA football pitch covers about 0.7 hectares, and Central Park in New York is approximately 341 hectares. Farms across Europe, Latin America, Africa, and Asia are sized in hectares (a small family farm might be 5–20 ha). The hectare relates to the square meter (1 ha = 10,000 m²), the square kilometer (100 ha = 1 km²), the acre (1 ha ≈ 2.471 acres), and the square mile (1 ha ≈ 0.00386 mi²). It is one of the few non-SI units accepted for use with SI for legal land measurement.

• European farm, vineyard and orchard size
• Forestry and conservation land
• Large construction projects and urban development

What is the Square Mile?

The square mile equals exactly 2.589988110336 square kilometers (or 640 acres) and is the American unit for measuring large geographic areas: counties, states, watersheds, and large parks. The continental United States covers about 3 million square miles, and Texas alone is 268,597 mi². Population density in US contexts is given in people per square mile (e.g., New York City has about 27,000 people/mi²). The square mile relates to the acre (640 acres = 1 mi²), the square kilometer (1 mi² ≈ 2.59 km²), the square foot (1 mi² = 27,878,400 ft²), and the hectare (1 mi² ≈ 259 ha). It is the natural large-area unit for American geographic discussion, though metric countries use square kilometers for the same purpose.

• US states, counties and cities
• UK geographic and historical boundaries
• Large estate and national-park reporting in Anglo contexts