Metric System FAQ
Frequently asked questions about the metric system and SI units.
The metric system is a decimal-based measurement system using meters, grams, and liters. It is the international standard for measurement.
All but three countries (US, Liberia, Myanmar) officially use the metric system, though even these countries use it for science.
SI stands for "Système International d'Unités" (International System of Units), established in 1960.
The 7 SI base units are: metre (m), kilogram (kg), second (s), ampere (A), kelvin (K), mole (mol), and candela (cd).
It uses base-10, so converting between units involves simply moving the decimal point. 1 km = 1,000 m = 100,000 cm.