How Big Is an Acre? Putting Land Area in Perspective
An acre is 43,560 square feet (about 4,047 square meters). Learn how it compares to a football field, a city block, and a hectare.
The Size of an Acre in Numbers
An acre is defined as exactly 43,560 square feet. In metric terms that is 4,046.856 square meters, or about 0.4047 hectare. It is also 4,840 square yards. These are exact by definition, so an acre never changes.
Our acres to sq ft converter and acres to hectares converter show any value directly.
Acre Next to Familiar Spaces
Everyday comparisons
An acre is slightly smaller than a standard American football field (about 57,600 sq ft including the end zones), roughly 75 percent of one.
A typical US suburban lot is often a quarter acre (about 10,890 sq ft).
One hectare (2.471 acres) is a square about 100 m on a side.
Why the Acre Persists in the US
The acre comes from old English land measurement and stayed in US customary use for homes, farms, and ranches. It is the unit Americans use when they buy property, even though science and most of the world use hectares and square meters.
For how US and metric units compare across the board, see our US customary vs metric guide.
Frequently Asked Questions
How many square feet are in an acre?
Exactly 43,560 square feet make 1 acre.
How big is an acre compared to a football field?
An acre (43,560 sq ft) is about 75 percent of a football field including end zones (about 57,600 sq ft).
How many square meters are in an acre?
4,046.856 square meters, or about 0.4047 hectare.
How many acres are in a hectare?
Exactly 2.47105 acres make 1 hectare.
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Quick Summary
An acre is exactly 43,560 square feet (4,046.856 sq m, about 0.4047 hectare). It is roughly three-quarters of an American football field including end zones, and a typical suburban lot is about a quarter acre.
Related Guide
US Customary vs Metric: A Complete Guide to Both Systems
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Disclaimer
Unit conversions on this site use internationally recognized, fixed conversion factors (for example, 1 inch = 2.54 cm, 1 pound = 0.45359237 kg, 1 °F = (°C × 9/5) + 32). They are provided for general, informational, and educational use. For applications where accuracy is critical — such as medical dosing, engineering, scientific research, trade, or legal compliance — always verify results against authoritative sources such as the U.S. National Institute of Standards and Technology (NIST) and the official International System of Units (SI) brochure, and follow any applicable local standards.
Exact Constants & Authoritative Sources
Every conversion on this page uses the fixed, internationally agreed constants below — drawn from NIST and the SI Brochure. No values are estimated or rounded as if exact. See the full list on our Sources & Standards page.
- EXACT1 acre = 4046.8564224 square metres (exact, 43,560 ft²)
- EXACT1 hectare (ha) = 10,000 square metres (definition)
- EXACT1 square foot (ft²) = 0.09290304 m² (exact)
- EXACT1 square mile = 2.589988110336 km² (exact)
Common Pitfalls & How to Avoid Them
Acre is not a square
An acre is 43,560 ft² of area in any shape — it can be long and thin. One acre = 4046.86 m² = 0.404686 hectare.
Section vs. hectare
A US "section" is 1 square mile = 259 ha. A hectare (10,000 m²) is ~2.47 acres. Keep the two apart when reading land listings.
A unit-conversion reference site has no manufacturer-specific or device calibration parameters, so "layered tuning" does not apply here. The only real error-handling is input validation: the converter rejects non-numeric, empty, or out-of-range entries and shows a clear message, then falls back to exact constants above. No estimated or rounded figures are ever presented as exact.
Authoritative sources for this page
- NIST (U.S. National Institute of Standards and Technology) — NIST SP 330 — The International System of Units (SI), 2019 edition
- BIPM (International Bureau of Weights and Measures) — SI Brochure — The International System of Units (9th edition)
Last Updated 2026 | This article was reviewed for accuracy