Square Feet to Acres
Convert square feet to acres with the exact factor (1 acre = 43,560 sq ft), a quick reference table, and common land-area examples.
sq ft to acre formula
To convert square feet (sq ft) to acres, divide by 43,560, because 1 US acre is defined as exactly 43,560 square feet.
Quick reference: sq ft to acre
Common values
1000 sq ft = 0.023 acre
4356 sq ft = 0.1 acre
10000 sq ft = 0.23 acre
43560 sq ft = 1 acre
87120 sq ft = 2 acre
Worked example
Convert 43,560 sq ft to acres:
43,560 ÷ 43,560 = 1 acre
So 43,560 square feet is exactly 1 acre.
Why convert sq ft to acre?
US homes and land are measured in square feet, while larger plots are quoted in acres. This conversion links lot size to acreage.
You can also use our calculator or read the paired guide acre reference.
Frequently Asked Questions
How many square feet are in an acre?
1 acre = 43,560 sq ft.
How do I convert 10,000 sq ft to acres?
10,000 ÷ 43,560 ≈ 0.2296 acre.
How many acres is a 0.5-acre lot in sq ft?
0.5 × 43,560 = 21,780 sq ft.
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Acres to Square Feet Converter
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Square Feet to Square Meters Converter
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Quick Summary
sq ft to acre uses a single exact factor. Use the formula above or the reference table for quick, accurate results.
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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