Square Foot (ft²)

US & ImperialCurrent unit

Exactly 0.09290304 m². The standard unit for floor areas and real estate in the US, UK and India.

1 square foot = 0.09290304 square meters (exactly).

About the square foot

Feet came first, and they were not all the same length. As a body-based unit, the foot ranged historically between about 250 and 335 millimeters, with ancient Greek and Roman feet near 300 mm. In medieval England a statute foot was set at 10/11 of an older Belgic foot, and Charlemagne's attempt around 790 to standardize units largely failed. The square foot is simply that length squared, so its size changed along with the foot.

The 1959 international agreement fixed the foot at exactly 0.3048 meter, so one square foot is exactly 0.09290304 m², or 144 square inches. The United Kingdom adopted the new foot in 1964. Today the square foot is the usual way of listing property in the United States, Canada, the United Kingdom, India, Pakistan, Singapore and Hong Kong, although the measuring convention varies: agents may measure corner to corner, subtract unheated space, or add heated space that extends beyond the end-to-end measurement. The world's smallest park has been reported at 2.6 sq ft.

Sources: Wikipedia: Square foot; Wikipedia: Foot (unit); NIST Guide to the SI, Appendix B.8: conversion factors

Square Foot conversion chart

1 square foot expressed in every other area unit:

More US & Imperial units

• square inch (area)
• square yard (area)
• acre (area)
• square mile (area)
• square rod (area)
• square chain (area)
• inch (length)
• foot (length)
• yard (length)
• mile (length)
• thou (length)
• league (length)
• furlong (length)
• chain (length)
• rod (length)
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