Square Feet to Square Kilometers (ft² to km²)

1 square foot equals 9.290304×10⁻⁸ square kilometers exactly.

1 square foot = 9.290304×10⁻⁸ square kilometers

How to convert square feet to square kilometers

To convert square feet to square kilometers, multiply the number of square feet by 9.290304×10⁻⁸. This factor is exact. To go the other way, multiply square kilometers by 10,763,910.42 (rounded).

square kilometers = square feet × 9.290304×10⁻⁸

Example: 10 square feet = 9.290304×10⁻⁷ square kilometers.

About these units

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.

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.

1 square foot = 0.09290304 square meters (exactly).

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

Square Kilometer (km²)

Metric (SI)Current unit

One million square meters (100 hectares). Used for the area of cities, countries and lakes.

Metric land measure took a surprisingly long time to settle on the kilometer. The meter was defined in 1799, yet people initially preferred the myriameter, 10,000 meters, and the French phrase myriamètres par heure was still in print in 1802. The Netherlands adopted the kilometer in 1817 under the name mijl. Once the kilometer was established, the square kilometer followed naturally as the unit for areas too large to count comfortably in hectares or square meters.

One square kilometer is 1,000,000 square meters, or 100 hectares, about 0.3861 square miles or 247.1 acres. A useful picture comes from history: many medieval European cities were enclosed by walls around roughly a square kilometer, with Delft at about 0.9 km² and Lucca at about 1.09 km². A standard 18-hole golf course of 6,000 meters needs about 0.8 km². The symbol km² means the square of a kilometer, not a thousand square meters. The planned Square Kilometre Array radio telescope takes its name from the collecting area it aims for.

1 square kilometer = 1,000,000 square meters (exactly).

Sources: Wikipedia: Square kilometre; Wikipedia: Kilometres per hour

Related conversions

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