How many hectares are in an acre?

1 acre is about 0.4047 hectares. The exact figure is 0.40468564224 ha, because 1 ac = 4,046.8564224 m² and 1 ha = 10,000 m². To go the other way, use hectares to acres.

How many hectares is a 160-acre farm?

160 acres is about 64.75 hectares (64.7497 ha). That is one quarter of a square mile.

How many hectares are in a square mile?

1 square mile is 640 acres, or about 259.0 hectares (258.998811 ha). In SI terms that is about 2.59 km².

How do I convert acres to hectares by hand?

Multiply the acres by 0.404686. For 100 acres that gives about 40.47 ha. See the area definitions and worked example for the underlying definitions.

Acres to Hectares (ha) Converter

Enter a value to instantly convert between area units.

From

Precision4 dp

1 Acre = 0.4047 Hectare

Key Formulas

Acre → Square Foot

ft² = ac × 43560

Square Foot → Acre

ac = ft² × 0.0000229568

Hectare → Acre

ac = ha × 2.47105

Acre → Hectare

ha = ac × 0.404686

Formula

ha = ac × (4046.8564224 / 10000)

To convert acres to hectares, multiply by 0.40468564224, which is 4,046.8564224 m² per acre divided by 10,000 m² per hectare. This converter uses the international acre of 43,560 square feet, built on the 0.3048 m foot. Land listings, farm subsidies, and forestry reports mix the two units, so 10 acres comes to 4.0468564224 ha, or about 4.05 ha. Dividing by the rounded 2.47105 acres per hectare drifts in the later digits, so the full factor suits precise work.

Source: NIST revised international-foot land factors; SP 811 Chapter 5 and Appendix B.8 (definition-derived arithmetic)

Reviewed by the Convert Calc editorial team · Last reviewed: 2026-10-06 · see our methodology

Frequently Asked Questions

Real-World Examples

One-acre suburban plot, restated in hectares for an overseas buyer.

1 ac = 0.4046856422 ha

A 10-acre hobby farm on a registry form that asks for hectares.

10 ac = 4.046856422 ha

A 100-acre pasture priced per hectare by a foreign buyer.

100 ac = 40.46856422 ha

One square mile of ranchland (640 ac) in hectares.

640 ac = 258.998811 ha

acres to sq feet sq feet to acres hectares to acres sq meters to sq feet sq feet to sq meters

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