Convert Hectares (ha) to Acres (ac)

What Is a Hectare?

The hectare (ha) is a metric unit of area equal to exactly 10,000 square meters — the area of a square with 100-meter sides. It is accepted for use with the International System of Units (SI), and the BIPM SI Brochure states that its use is expected to "continue indefinitely."

Introduced in 1795 as part of the French metric system, the hectare is the global standard for reporting land area in agriculture, forestry, urban planning, and environmental science. Most countries outside the US express farm sizes, forest cover, and protected areas in hectares.

Key equivalences: 1 ha = 10,000 m² = 100 ares = 0.01 km².

What Is an Acre?

The acre (ac) is a unit of land area in the US customary and British imperial systems. It is defined as the area of a rectangle measuring one chain (66 feet) by one furlong (660 feet), which equals exactly 43,560 square feet or 4,046.8564224 m².

The word "acre" derives from the Old English æcer, originally meaning the amount of land a yoke of oxen could plow in one day. Today it remains the primary land unit in the United States, the United Kingdom (in everyday real estate), Canada, and several former British colonies.

Key equivalences: 1 acre = 43,560 ft² = 4,840 yd² = 1/640 of a square mile.

Hectares to Acres Formula

The conversion factor derives from the exact definitions of both units:

acres = hectares × 2.4710538146717 exact

This comes from dividing one hectare (10,000 m²) by the exact metric equivalent of one acre (4,046.8564224 m²). For practical use, hectares × 2.471 is accurate to four significant figures.

Worked Example

Convert 50 hectares to acres:

1. Multiply: 50 × 2.4711 = 123.55 acres

So a 50-hectare property — common for a mid-size European farm — is about 123½ acres. The average US farm is approximately 189 hectares (466 acres), according to the 2024 USDA Farms and Land in Farms survey.

Quick Estimation

For mental math, multiply hectares by 2.5 — this overshoots by only 1.2%. Example: 200 ha × 2.5 = 500 acres (exact: 494.2 acres). Alternatively, double the hectares and add half: 200 × 2 = 400, plus 200 ÷ 2 = 100, total = 500.

Common Conversions at a Glance

Which Is Bigger: Hectare or Acre?

A hectare is about 2.47 times larger than an acre. Put another way, you need roughly 2½ acres to make one hectare. A single hectare covers 10,000 m² — approximately the size of a regulation rugby pitch — while an acre covers 4,047 m², roughly 75% of an American football field.

When You Need This Conversion

• International land transactions: A European property listed at 50 hectares is about 123.5 acres. US buyers, investors, and appraisers need the acre figure to judge value against local comparable sales and familiar benchmarks.
• Agricultural trade and reporting: Global crop production statistics from the FAO use hectares, while the USDA reports in acres. A Brazilian soybean farm of 500 ha produces on about 1,236 acres — conversion is routine in commodity analysis.
• Forestry and conservation: International forestry certifications (FSC, PEFC) and biodiversity reports use hectares. US timber companies manage in acres — a 10,000 ha managed forest covers about 24,711 acres.
• News and media: International reports on wildfires, deforestation, and land-use change use hectares. A 5,000 ha wildfire covers about 12,355 acres — the acre figure helps US and UK audiences grasp the scale.