CALCZERO.COM

Area Converter

Convert square feet, meters, acres, hectares—26 units total. Room calculator included.

Quick Reference
1 ft² = 0.0929 m² | 1 acre = 0.4047 hectares | 1 acre = 43,560 ft²
Quick:

Quick Reference - Popular Conversions

From To Multiply By Example
Square Feet Square Meters 0.092903 1000 ft² = 92.9 m²
Square Meters Square Feet 10.7639 100 m² = 1,076.4 ft²
Acres Hectares 0.404686 5 ac = 2.02 ha
Hectares Acres 2.47105 2 ha = 4.94 ac
Square Miles Square Kilometers 2.58999 1 mi² = 2.59 km²
Acres Square Feet 43,560 1 ac = 43,560 ft²
Hectares Square Meters 10,000 1 ha = 10,000 m²
Square Yards Square Meters 0.836127 100 yd² = 83.6 m²

Mental Math Shortcuts

Quick Estimates:
  • 1 m² ≈ 10.76 ft² (round to 11)
  • 1 ft² ≈ 0.093 m² (about 1/11 m²)
  • 1 acre ≈ 4,000 m² (exact: 4,047)
  • 1 hectare ≈ 2.5 acres (exact: 2.471)
  • 10 ft² ≈ 1 m² (ballpark)
  • 100 m² ≈ 1,000 ft² (ballpark)

How to Use This Converter

Three modes: convert between two units, see all units at once, or calculate area from room dimensions.

Metric Area Units

The square meter is the base. Hectare (10,000 m²) handles farms and land. Square kilometer covers cities and regions.

Imperial Area Units

US real estate runs on square feet, land parcels on acres (43,560 ft² each), regions on square miles (640 acres). The acre's odd number comes from ox plowing distances. Square yards show up for carpet. UK and Canada use these too.

Acres or Hectares?

  • Acres: United States
  • Hectares: Europe, Asia, Africa, South America, Australia
  • Both: UK, rural Canada

1 hectare = 2.47 acres—multiply hectares by 2.5 for a quick estimate, or acres by 0.4. An acre covers 90% of a football field; a hectare is 100m × 100m.

Watch Out For: The Square Factor

Area conversions require squaring the linear factor.

Feet to meters is 0.3048, but square feet to square meters is 0.3048² = 0.0929. A 10×10 ft room (100 ft²) = 3.048×3.048 m = 9.29 m², not 30.48 m². Using the wrong factor triples your error. Volume conversions cube the factor.

How Square Footage Gets Measured

US listings quote gross living area to exterior walls, excluding garages. European listings use usable floor space—smaller numbers for identical homes. Average sizes: USA ~2,300 ft², Australia ~2,000 ft², UK ~820 ft², Hong Kong under 500 ft².

US Land Survey System

The 1785 grid divided land west of the original colonies into townships (6 mi × 6 mi, containing 36 sections). One section = 1 square mile = 640 acres. Rural deeds use descriptions like "NW quarter of Section 12, Township 3 North, Range 2 West."

International Area Units

Dunam (Middle East): 1,000 m². Bigha (India): 1,500-6,000+ m² depending on state. Mu (China): 667 m². Rai (Thailand): 1,600 m². Tatami (Japan): 1.65 m², used for room sizes. Pyeong (Korea/Taiwan): 3.3 m². Bigha in Bihar differs from West Bengal—verify local definitions.

Area Formulas

Rectangle: length × width
Square: side²
Circle: π × radius²
Triangle: ½ × base × height
Trapezoid: ½ × (a + b) × height

For irregular shapes, break them into rectangles and triangles and add up the pieces.

Quick Math

  • ft² to m²: × 0.093
  • acres to hectares: × 0.4
  • hectares to acres: × 2.5

For legal docs, use exact factors—the 0.4 vs 0.404686 difference means a 100-acre farm is 40.47 hectares, not 40.

Quick Answers

How many square feet in an acre?
43,560 ft². A square acre would be 208.7 feet on each side.
Which is bigger, a hectare or an acre?
Hectare. One hectare = 2.47 acres.