SI Units & Prefixes

About SI Units & Prefixes

This SI reference gathers the complete metric prefix ladder and the units of the International System on one page: all 24 prefixes from quecto (10⁻³⁰) to quetta (10³⁰), the 7 base units, and the 22 named derived units such as the newton, pascal, joule, watt, volt, ohm and sievert.

Three tabs keep the material organized. The prefixes tab shows each name, symbol, power-of-ten factor and full decimal form; the base units tab pairs metre, kilogram, second, ampere, kelvin, mole and candela with the quantity they measure and their current SI definition; the derived units tab expresses every named unit in base units.

A search box filters the active tab and highlights the matched text, and each symbol, factor and base-unit expression has its own copy chip — handy for engineering notes, lab reports and anyone double-checking whether that prefix is pebi or peta.

How to use SI Units & Prefixes

1. Pick a tab: SI prefixes, base units or named derived units — each tab badge shows how many entries it holds.
2. Type in the search box to filter the current tab; the matching part of each name is highlighted.
3. On the prefixes tab, read each prefix’s symbol, power-of-ten factor and its full decimal form.
4. On the base and derived tabs, check the quantity each unit measures, its definition or its expression in base units.
5. Click any copy chip to copy a symbol, factor or base-unit expression to your clipboard.

Frequently asked questions