How do I convert acre to ha?

Use the formula shown above or enter a value to see acre converted to ha instantly.

What is the formula for acre to ha?

The converter calculates ha by applying the category-specific conversion factor for Area.

acre and ha are both part of the Area category; pick the unit that matches your measurement context (e.g., scale, region, or industry standard).

Area Converter & Surface Reference

Use the live converter below to translate between Acre (acre) and Hectare (ha). Scroll further for quick examples, formula tips, and related units.

Formula insight: Most unit conversions use a simple multiplication or division by a conversion factor. The calculator shows the exact formula used.

Convert

Acre

acre

Hectare

0.4047

Rounded result (4 decimals max)

Formula

1 acre = 0.4047 ha

Conversion sourcesTap or click to view references

The International System of Units (SI) — NIST Special Publication 330
National Institute of Standards and Technology (NIST). The SI Brochure (SP 330) is the definitive English edition of the BIPM SI tables. NIST’s edition lists the official constants and conversion factors tying inch-pound units to SI, which SwapUnits applies for length, mass, temperature, pressure, volume, and related conversions. See /standards/nist-si-tenfold for the complete decimal multiple/submultiple table. View source · View SI table

Results update as you type. Swap the direction to convert back from ha to acre.

Multiply any row by the same factor to scale results. Use the converter above to enter exact values with your own units.

Keep the reciprocal handy when double-checking calculations or undoing a conversion.

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View the full unit roster, charts, and tips for Area Converter & Surface Reference conversions.