Area Converters 8
Area is length squared. When you round a length conversion and then square it, the error grows fast. Rounding 0.3048 to 0.3 costs you 3% on the linear dimension — square it and you're off by 6.2%. These converters use the exact constants: 1 ft = 0.3048 m, 1 acre = 43,560 sq ft, 1 hectare = 10,000 m². No shortcuts.
Read the Area Conversion Guide
The acre (43,560 ft² from oxen and a plow), the hectare (10,000 m² the world farms in), the square-foot-to-square-meter code gap, and the 2023 US survey-foot retirement that moved every surveyed acre by a few parts per million.
Open the full guide →Area: When Rounding Error Gets Squared
Area conversion carries a hidden danger that length conversion does not: rounding error gets squared. If you convert feet to meters with 3 decimal places (1 ft = 0.305 m), your length error is 0.15%. But when you square that to get area, your error becomes 0.3%. For a 10-acre plot, that's ± 1,300 square feet — the size of a small house. Civil engineers, real estate surveyors, and GIS specialists all learn this lesson the hard way.
The acre has a deeply agricultural origin: it was defined as the amount of land one yoke of oxen could plow in a single day — standardized to 43,560 square feet (1 chain × 1 furlong, or 66 ft × 660 ft). The hectare (10,000 m², or a square 100 m on each side) is the modern agricultural standard used worldwide. The US Survey Foot (1 ft = 1200/3937 m) created a separate set of area units — the survey acre — which was formally deprecated by NIST on January 1, 2023. Every acre surveyed before that date used a slightly different definition.
Area Conversion Constants
1 acre = 43,560 sq ft = 4,046.8564224 m²
1 hectare = 10,000 m² = 2.47105 acres
1 sq mile = 640 acres = 2.589988110336 km²
1 sq ft = 0.09290304 m² (exact, from 1 ft = 0.3048 m)
For the full story of the 2023 survey-foot retirement and what it means for every surveyed property in the US, see the Area Conversion Guide.
How the World Measures Land — and Why It Can't Agree on a Single Unit
No unit of measurement is more politically and economically charged than the unit of land area. Property taxes are assessed per acre or per hectare. Agricultural subsidies are paid per hectare. Real estate is listed per square foot or per square meter. A country's choice of land unit is locked into its legal code, its cadastral surveys, and its tax base — and switching units means re-surveying every parcel in the nation.
The acre is still the legal land unit in the United States, Canada (though metric is official), the UK (alongside the hectare), India, Pakistan, and much of the former British Empire. The hectare dominates the European Union, Australia, New Zealand, South America, and most of Africa and Asia. The mu (亩, 666.67 m²) is the standard unit in China — 15 mu to the hectare. The bigha in South Asia varies from 1,600 to 6,800 m² depending on the state. None of these convert to acres or hectares in round numbers. Every cross-border land transaction, every international agricultural report, and every FAO crop yield statistic runs through an area converter — and the World Bank's agricultural data is published in hectares regardless of what unit the source country uses.
Construction Cost: $/sq ft vs $/sq m — the Bid That Crosses a Border
1 sq m = 10.7639 sq ft — the construction estimator's conversion card
$100/sq ft = $1,076.39/sq m — US pricing in international units
€2,000/sq m ≈ $200/sq ft — European pricing in US units (at €1 = $1.08)
1 acre = 4,046.86 m² — land acquisition across metric borders
International construction firms bidding across borders convert area costs as a matter of contract survival. A European contractor bidding a US project receives plans in square feet and must price in square meters to use internal cost databases. The conversion runs in both directions on every line item: concrete (per m³), formwork (per m² of contact area), flooring (per sq ft or per m² depending on the supplier), and land (per acre or per hectare). The firm that rounds the area factor loses the bid by appearing expensive or wins it and loses money on the job. Every estimator carries the exact factor: 0.09290304 for sq ft to sq m, and its reciprocal 10.7639. Rounding either is a career-limiting move.
Square Feet ↔ Square Meters
Acres, Hectares & Square Feet
Square Miles ↔ Square Kilometers
Square Meters & Acres — Land Lots & Fields
Hectares & Square Feet — Farms & Development Sites
Exact conversion factors
Area factors are length factors squared, and the squaring is where most errors come from. The table gives the exact values so a squared factor never has to be reconstructed by hand.
| From | To | Exact factor | Basis |
|---|---|---|---|
| 1 acre | square meters | 4,046.8564224 | Exact, 4,840 square yards |
| 1 hectare | square meters | 10,000 | Exact, a square 100 m on each side |
| 1 square foot | square meters | 0.09290304 | Exact from 1 ft = 0.3048 m |
| 1 square inch | square centimeters | 6.4516 | Exact from 1 in = 2.54 cm |
| 1 square yard | square meters | 0.83612736 | Exact, 9 square feet |
| 1 square mile | square kilometers | 2.58998811034 | From 1 mile = 1.609344 km, squared |
| 1 acre | hectares | 0.40468564224 | Exact ratio of the two definitions |
| 1 square meter | square feet | 10.7639104167 | Derived, squared factor |
| 1 hectare | acres | 2.47105381467 | Derived from the exact definitions |
| 1 acre | square feet | 43,560 | Exact, 43,560 by definition |
Frequently asked questions
How many square feet are in an acre?
Exactly 43,560. That is 4,840 square yards, or a square 208.71 feet on a side. The figure descends from the chain and furlong rather than from any metric conversion.
Is a hectare bigger than an acre?
Yes, about 2.471 times bigger. A hectare is 10,000 square meters and an acre is 4,046.86 square meters, so 100 hectares is roughly 247 acres.
Why is one square meter not 3.28084 square feet?
Because the factor has to be squared. One meter is 3.28084 feet, so one square meter is 3.28084 times 3.28084, which is 10.7639 square feet. Cubic units need the factor cubed.
What is the practical difference between an acre and a hectare?
Little on the ground, a lot on paper. Land registries, subsidy schemes and yield figures are quoted in hectares in most countries and in acres in the United States, so contracts must state which.