Metre

The bar, made of Platinum and Iridium that defined the length of a metre until 1960.

A metre (US spelling, meter) is the basic unit of length in the SI measurement system. The abbreviation for the metre is m. According to the earliest definition (dating to the French Revolution), it was 1/10,000,000th (one ten-millionth) of the distance between the Earth's equator and the North Pole along the Paris meridian. The metre is now officially defined as the distance light travels in a vacuum in 1/299,792,458th of a second.

In the imperial system of measurement, one metre is equal to about 39.37 inches, 3.28 feet, or about 1.09 yards.

Units based on the metre

• 0.000000000000000000000001 Ym (yottametre) = 1 m
• 0.000000000000000000001 Zm (zettametre) = 1 m
• 0.000000000000000001 Em (exametres) = 1 m
• 0.000000000000001 Pm (petametres) = 1 m
• 0.000000000001 Tm (terametres) = 1 m
• 0.000000001 Gm (gigametres) = 1 m
• 0.000001 Mm (megametres) = 1 m
• 0.001 km (kilometres) = 1 m
• 0.01 hm (hectometres) = 1 m
• 0.1 dam (decametres) = 1 m
• 1 m
• 10 dm (decimetres) = 1 m
• 100 cm (centimetres) = 1 m
• 1000 mm (millimetres) = 1 m
• 1,000,000 μm (micrometres) = 1 m
• 1,000,000,000 nm (nanometres) = 1 m
• 1,000,000,000,000 pm (picometres) = 1 m
• 1,000,000,000,000,000 fm (femtometres) = 1 m
• 1,000,000,000,000,000,000 am (attometres) = 1 m
• 1,000,000,000,000,000,000,000 zm (zeptometres) = 1 m
• 1,000,000,000,000,000,000,000,000 ym (yoctometres) = 1 m

*Note: units in bold are the most commonly used.

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