The International System of Units (abbreviated as SI) is the modern form of the metric system, and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units (ampere, kelvin, second, metre, kilogram, candela, mole) and a set of twenty decimal prefixes to the unit names and unit symbols.

Obecnie układ SI zawiera 7 jednostek podstawowych: metr (m), kilogram (kg), sekunda (s), amper (A), kelwin (K), kandela (cd), mol (mol)-liczebność materii.

Derzeit enthält das SI-System 7 Grundeinheiten: Meter (m), Kilogramm (kg), Sekunde (n), Ampere (A), Kelvin (K), Candela (cd), Mol (Mol) - Materie Größe.