Understanding Area Conversions
Area measures two-dimensional space — length times width. Every unit in this converter is defined relative to the square meter. Here's the math behind each conversion, the history of each unit, and the practical contexts where they matter most.
How Area Conversion Works
All area units in this converter share a common base: the square meter (m²). To convert between any two units, the value is first expressed in square meters, then divided by the target unit's square-meter equivalent. The general formula is:
Result = Value × (source unit in m²) ÷ (target unit in m²)
For example, converting 2 acres to square meters: 2 × 4,046.856 ÷ 1 = 8,093.71 m². Area conversions involve squared relationships — doubling a linear dimension quadruples the area, which is why the conversion factors can seem large.
Conversion Factors: Every Unit Explained
The exact relationship of each unit to one square meter — the factor our converter uses internally — along with history and primary use cases.
Square Meter (m²)
Factor: 1 (base unit)
The SI unit of area — the area of a square with sides of one meter. Square meters are the standard for residential floor plans, room sizes, and construction measurements in metric countries. A typical parking space is roughly 12 m².
Square Kilometer (km²)
Factor: 1 km² = 1,000,000 m²
One million square meters — the area of a square with 1 km sides. Used for measuring cities, countries, lakes, and large geographic regions. For reference, Manhattan is about 59 km² and the United Kingdom is approximately 243,610 km².
Square Centimeter (cm²)
Factor: 1 cm² = 0.0001 m²
One ten-thousandth of a square meter. Used for small surface areas like postage stamps, cross-sections in engineering, and skin area in dermatology. A credit card has an area of roughly 46 cm².
Square Millimeter (mm²)
Factor: 1 mm² = 0.000001 m²
One millionth of a square meter. Essential in precision engineering, electronics, and material science. Wire cross-sections, semiconductor die sizes, and mechanical tolerances are commonly specified in mm². A grain of sand is roughly 1 mm².
Hectare (ha)
Factor: 1 ha = 10,000 m²
A square 100 meters on each side. The hectare is the international standard for agricultural land measurement, forestry, and urban planning outside the US. It was introduced during the French Revolution alongside the metric system. One hectare is approximately 2.47 acres.
Square Mile (mi²)
Factor: 1 mi² = 2,589,988.11 m²
The area of a square one statute mile on each side — about 640 acres or 259 hectares. Used for measuring counties, states, and national parks in the US. A "section" in the US Public Land Survey System is exactly one square mile (640 acres).
Square Yard (yd²)
Factor: 1 yd² = 0.836127 m²
Nine square feet. Commonly used in the US and UK for carpet, flooring, and fabric pricing. A standard football field (US) is about 5,333 square yards. In construction, concrete and paving are sometimes quoted per square yard.
Square Foot (ft²)
Factor: 1 ft² = 0.092903 m²
The dominant unit for real estate in the United States. Home sizes, office spaces, and rental listings are quoted in square feet. A typical US two-bedroom apartment is 800–1,000 ft². One square foot equals exactly 144 square inches.
Square Inch (in²)
Factor: 1 in² = 0.00064516 m²
Used for small surface measurements in the US — screen areas, paper sizes, and pressure (PSI = pounds per square inch). A standard letter-size sheet of paper (8.5" × 11") has an area of 93.5 in². Display sizes are measured diagonally but actual screen area is in square inches.
Acre (ac)
Factor: 1 ac = 4,046.856 m²
Historically defined as the amount of land a yoke of oxen could plow in one day. Today, one acre equals exactly 43,560 square feet (roughly 208.7 ft × 208.7 ft). It is the standard land measurement unit in the US, UK, and many former British colonies. A football field (including end zones) is about 1.1 acres.
Common Area Conversions at a Glance
Quick reference for the area conversions people search for most frequently.
| From | To | Formula | Example |
|---|---|---|---|
| Square Meters | Square Feet | m² × 10.7639 | 100 m² = 1,076.39 ft² |
| Square Feet | Square Meters | ft² × 0.092903 | 1,500 ft² = 139.35 m² |
| Acres | Hectares | ac × 0.404686 | 10 ac = 4.047 ha |
| Hectares | Acres | ha × 2.47105 | 5 ha = 12.36 ac |
| Square Miles | Square Kilometers | mi² × 2.58999 | 1 mi² = 2.59 km² |
| Acres | Square Feet | ac × 43,560 | 0.5 ac = 21,780 ft² |
Why Area Conversions Are Squared
A common mistake is to apply a linear conversion factor to area. If 1 foot = 0.3048 meters, it might seem like 1 square foot = 0.3048 square meters. But area is two-dimensional — both length and width must be converted.
1 ft² = (0.3048 m) × (0.3048 m) = 0.3048² m² = 0.092903 m²
The linear factor is squared because area is length × width
This squared relationship explains why area conversion factors can seem counterintuitively large. One mile is 1.609 km, but one square mile is 2.59 km² — not 1.609 km². The further you go from the base unit, the more dramatic the difference becomes.
The History of Area Measurement
The Acre: Oxen and Medieval Farming
The acre traces back to medieval England, where it was defined as the amount of land a pair of oxen could plow in a single day. The shape was typically a long strip — one furlong (660 feet) by one chain (66 feet) — giving 43,560 square feet. This shape was practical: long, narrow strips minimized the number of times the plow team had to turn around. The acre remains the standard land unit in the US, despite having no relationship to the metric system.
The Hectare: Revolutionary Rationalism
The hectare was introduced in 1795 during the French Revolution as part of the metric system's push to replace inconsistent local units. It was designed to be intuitive: 100 meters × 100 meters = 10,000 m². The prefix "hecto" means 100 (100 ares, where 1 are = 100 m²). Today, it is the globally accepted unit for agricultural land area and is used in land registries throughout Europe, Asia, South America, and Africa.
The Square Meter: Universal Standard
As the SI derived unit for area, the square meter inherits its definition from the meter itself. One square meter is the area of a square whose sides are each one meter — which, since 2019, means sides equal to the distance light travels in 1/299,792,458 of a second. In practice, sq m is used for floor plans, room dimensions, and construction globally.
Real-World Area References
Area numbers can be hard to visualize. Here are some real-world benchmarks to help you calibrate.
Small Scale
- Credit card: ~46 cm² (7.1 in²)
- Sheet of paper (A4): 623.7 cm² (96.7 in²)
- Parking space: ~12 m² (129 ft²)
- Studio apartment: ~30 m² (323 ft²)
Medium Scale
- Tennis court: 260.87 m² (2,808 ft²)
- US median home: ~201 m² (2,164 ft²)
- Football field (US): ~5,351 m² (1.32 ac)
- City block (NYC): ~2 ha (5 ac)
Large Scale
- Central Park (NYC): 341 ha (843 ac)
- Manhattan: ~59 km² (22.8 mi²)
- Los Angeles: ~1,302 km² (503 mi²)
- State of Texas: ~696,241 km² (268,820 mi²)
Massive Scale
- Lake Michigan: 57,800 km² (22,317 mi²)
- United Kingdom: 243,610 km² (94,058 mi²)
- Amazon Rainforest: ~5,500,000 km²
- Earth's surface: 510,100,000 km²
Area Conversion FAQ
? How many square feet are in an acre?
One acre equals exactly 43,560 square feet. An acre is roughly the size of a football field (which is 48,000 sq ft including end zones). To convert acres to square feet, multiply by 43,560.
? How do you convert square meters to square feet?
Multiply the square meter value by 10.7639 to get square feet. For example, 100 square meters = 1,076.39 square feet. This is the most common conversion for comparing international real estate listings.
? How many acres are in a hectare?
One hectare equals approximately 2.47105 acres. A hectare is 10,000 square meters (100 m × 100 m). Hectares are the global standard for measuring agricultural land and large properties outside the United States.
? What is the difference between an acre and a hectare?
An acre (43,560 sq ft / 4,046.86 sq m) is an imperial unit used mainly in the US, UK, and former British colonies. A hectare (10,000 sq m / 107,639 sq ft) is a metric unit used internationally. One hectare is about 2.47 acres. Hectares are part of the metric system while acres are not.