Free Online Unit Converters

Convert between units instantly. Fast, free, and accurate.

Need to convert centimeters to inches, kilograms to pounds, or Celsius to Fahrenheit? Our unit converters handle all common measurement conversions instantly. We also offer specialized converters for binary and hexadecimal numbers, Roman numerals, and number-to-word translations. Every conversion uses precise conversion factors and updates results as you type.

Why Use Our Converters

Real-time conversion -- Results update instantly as you type, with no need to press a button or reload the page.
Precise conversion factors -- We use internationally recognized standards such as NIST and SI for all unit conversions.
Beyond basic units -- Convert binary to hex, numbers to English words, and Arabic to Roman numerals alongside traditional measurements.

Length Converter

Convert between length units

Weight Converter

Convert between weight units

Temperature Converter

Convert between temperature scales

Area Converter

Convert between area units

Speed Converter

Convert between speed units

Data Size Converter

Convert between data size units

Timezone Converter

Convert between timezones

Binary/Decimal/Hex Converter

Convert between number bases

Number to Words Converter

Convert numbers to words

Roman Numeral Converter

Convert Roman numerals

FAQ

How precise are the conversions?

Our converters use IEEE 754 double-precision floating point arithmetic and internationally standardized conversion factors. Results are accurate to at least 10 significant digits for all common unit conversions.

Do you support metric and imperial units?

Yes. Each converter supports both metric (SI) and imperial/US customary units. You can convert in either direction between systems like km/miles, kg/lbs, and Celsius/Fahrenheit.