Metric System Day

Metric System Day is observed next on Monday, April 7th, 2025 (323 days from today).

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April 7th every year is the anniversary of the metric system, also known as Metric System Day. The metric factor is used as a measurement factor in most countries of the world except the US. The metric system is introduced by France in 1799 and it is an original decimal-based measurement system based on meters and kilograms. "Decimal-based" means all units based on powers of 10. Yes, the base unit by a factor of 10 can change the base units and then a system of prefixes. Base units include kilograms, meters, and liters (liter is the lead unit of export). Prefixes include milli-, centi-, deci-, and kilo. The Kelvin scale or the Celsius scale is used in the metric system as the temperature, but the prefixes are not applied to the temperature degree. While the zero point is different between Kelvin and degrees Celsius, the magnitude of degrees is the same.

The metric system is sometimes abbreviated as MKS, indicating that the standard units are meters, kilograms, and seconds.

The metric system is used in almost every country so that it often used as a synonym for the SI or the International System of Units. The main exception is the United States, which has approved this system for use since 1866, which has yet to transition to SI as an official system of measurement.

History of Metric System Day

The SI units of measurement were decided upon after a series of international conferences organized by the standards organization, the International Institute of Metrology (BIPM). The SI was first named in 1960 and then added in 1971.

We can trace back to the 1640s to find out about the true origins of the SI, or metric system. French scientists invented Metric System and it was received great publicity by the French Revolution of 1789 to become more popular. The metric system tries to choose non-arbitrary units of measurement, while attached to the official ideology of the revolution is "pure reason"; it was a significant improvement over the units of measure prevailing at the time, since their values ​​were often regionally dependent.

The SI is built on the basis of the seven basic units of the SI, which are kilograms, meters, seconds, amps, kelvins, moles, and candela. These units are used to define other inferred units of measurement.

SI also defines a number of SI prefixes for use with the unit of measure: these prefixes combine with any unit of measure to produce its multiples or divisors. For example, the prefix kilo represents a multiple of thousands (thousand), so kilometers equal 1,000 meters, kilograms equal 1,000 grams, and so on. Also note that a millionth of a kilogram is a milligram, not a micro kilogram.

With a few exceptions (e.g. draft beer sold in the UK) the system can be legally used in any country in the world and many countries do not need to maintain definitions of other units of measure. Other countries that still recognize non-SI units (e.g. US or UK) need to define units of measure in terms of SI units; for example, a regular inch is defined as exactly 0.0254 meters. However, in the United States, geographical distances are not redefined due to the cumulative error it can leave and another reason is the survey foot and the survey inch (two units of length used in the field of work) are still separate units of measure. (This is not a problem for Britain, because the Ordnance Survey (the UK mapping organization) has been making metric maps since before World War II.)

How to observe Metric System Day

Spend the day Metric System Day learning more about the Metric, its specific units, what they mean, and how the metric system came to be to understand more about the Metric System. In addition, this holiday is also for you to express the necessity of the Meter coefficient to daily life. Share your Metric System Day on social media with the hashtag #MetricSystemDay.


Metric System Day has been observed annually on April 7th.


Friday, April 7th, 2023

Sunday, April 7th, 2024

Monday, April 7th, 2025

Tuesday, April 7th, 2026

Wednesday, April 7th, 2027

Also on Monday, April 7th, 2025

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