Area Converter
Convert area between square millimetres, centimetres, metres, kilometres, inches, feet, yards, acres, and hectares.
How to use this tool
- Enter area and from unit in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your square feet and the full breakdown beneath it.
Formula
All units convert to square metres first, then to the target unit:
m² = input × factorfrom
output = m² ÷ factorto
Key factors: mm² = 0.000001 m² | cm² = 0.0001 m² | km² = 1,000,000 m² | in² = 0.00064516 m² | ft² = 0.09290304 m² | yd² = 0.83612736 m² | acre = 4046.856 m² | ha = 10,000 m²
How it works
Area units are the square of their corresponding linear units, so the conversion factors are the squares of the length factors. Square metres serve as the base unit, and each input is converted to m² then redistributed to all output units in a single calculation pass.
A common mistake is applying a linear conversion factor to an area: if 1 foot = 0.3048 m, then 1 square foot = 0.3048² = 0.09290304 m², not 0.3048 m². Squaring the linear factor is essential for area conversions and is frequently forgotten when working manually.
Worked example
Convert 1 square metre to all area units
- Input: 1 square metre (from_unit = square_meter), so base = 1 × 1 = 1 m².
- mm²: 1 / 0.000001 = 1,000,000 mm². cm²: 1 / 0.0001 = 10,000 cm². km²: 1 / 1,000,000 = 0.000001 km².
- in²: 1 / 0.00064516 ≈ 1550.0031 in². ft²: 1 / 0.09290304 ≈ 10.7639 ft². yd²: 1 / 0.83612736 ≈ 1.196 yd².
- Acres: 1 / 4046.856 ≈ 0.000247 ac. Hectares: 1 / 10000 = 0.0001 ha.
1,000,000 mm² | 10,000 cm² | 1 m² | 0.000001 km² | 1550.0031 in² | 10.7639 ft² | 1.196 yd² | 0.000247 ac | 0.0001 ha
Common mistakes to avoid
- Squaring the linear factor incorrectly -- if 1 m = 100 cm, then 1 m2 = 10,000 cm2 (not 100 cm2), because area scales as the square of the linear dimension.
- Confusing hectares and acres -- 1 hectare = 2.471 acres, so a 5-acre plot is about 2 hectares, not 5.
- Entering square footage when the tool expects square metres, or vice versa, when copying values from property listings that use different regional conventions.
Key terms
- Square metre (m²)
- The SI unit of area, equal to the area of a square with 1-metre sides. Used in most countries for property and construction measurement.
- Acre (ac)
- An imperial unit of land area equal to 4046.856 m² or 43,560 square feet, commonly used for farmland and property in the US and UK.
- Hectare (ha)
- A metric unit of area equal to 10,000 m² (a 100 m × 100 m square). The standard unit for agricultural land measurement internationally.
- Square foot (ft²)
- An imperial area unit equal to 0.09290304 m², widely used in US real estate and construction for floor area.
Frequently asked questions
- How many square feet are in an acre?
- Exactly 43,560 square feet. An acre was historically defined as the area a yoke of oxen could plow in one day.
- What is the difference between a hectare and a square kilometre?
- 1 km2 = 100 hectares. A hectare is 10,000 m2 (100 m x 100 m), making it a convenient unit for farmland and parks.
- Why does converting square inches to square metres require dividing by 1,550, not 39.37?
- Because 1 m = 39.3701 in, so 1 m2 = 39.37012 = approximately 1,550.0 in2. Area units scale as the square of their linear counterparts.