Fast, accurate, and free metric conversion tools for students, professionals, and everyday use. Convert between metric units instantly with our comprehensive calculators.
Select from our comprehensive collection of metric converters
Convert between kilometers, meters, centimeters, millimeters, and more
8 convertersConvert between metric tons, kilograms, grams, milligrams, and more
8 convertersConvert between cubic meters, liters, milliliters, and cubic centimeters
10 convertersConvert between Celsius and Kelvin for scientific applications
2 convertersConvert between square kilometers, hectares, square meters, and more
8 convertersConvert between km/h, m/s, and meters per minute
6 convertersConvert between pascals, kilopascals, megapascals, bars, and millibars
8 convertersConvert between joules, kilojoules, megajoules, and kilowatt-hours
8 convertersConvert between watts, kilowatts, and megawatts
6 convertersConvert between newtons, kilonewtons, and meganewtons
6 convertersConvert between seconds, milliseconds, microseconds, minutes, hours, and days
12 convertersConvert between hertz, kilohertz, megahertz, and gigahertz
8 convertersConvert between bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes
10 convertersConvert between amperes, milliamperes, and microamperes
6 convertersConvert between volts, kilovolts, and millivolts
6 convertersAll conversions use exact NIST-standard conversion factors for precision you can trust
Real-time conversion as you type with no "calculate" button needed
Responsive design works perfectly on phones, tablets, and computers
Each converter includes formulas, examples, and learning resources
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Based on the International System of Units (SI) used by 95% of the world
The metric system, officially known as the International System of Units (SI), is the world's most widely used measurement system. Adopted by 195 countries, it provides a coherent, decimal-based framework for measuring everything from microscopic particles to astronomical distances.
The system is built on seven base units:
What makes the metric system powerful is its use of decimal prefixes (kilo-, centi-, milli-, etc.) that scale units by powers of 10, making conversions simple and intuitive. Since the 2019 redefinition, all SI units are now defined by fundamental constants of nature, ensuring their stability and reproducibility anywhere in the universe.
Our converters help you navigate this system whether you're a student learning conversions, a professional needing quick calculations, or anyone working with international measurements.