Free Converters Online

Last updated: April 2026

Free online converters for units, numbers, and data formats.

Our free online converters handle unit conversions, number base conversions, data format transformations, and more. Get instant, accurate results for length, weight, temperature, data size, and dozens of other conversion types without any software.

Binary to Decimal

Convert binary numbers to decimal, octal, and hexadecimal instantly. Free binary to decimal converter with bidirectional conversion. Great for students and programmers.

Decimal to Binary

Convert decimal numbers to binary, octal, and hexadecimal instantly. Free decimal to binary converter with grouped bit display. Perfect for students and developers.

Number to Words

Convert any number to words instantly. Free number to words converter that spells out numbers in English. Perfect for checks, legal documents, and invoices.

Roman Numeral Converter

Convert between Roman numerals and decimal numbers instantly. Free Roman numeral converter with a reference chart. Supports numbers 1 to 3999.

Temperature Converter

Convert temperatures between Celsius, Fahrenheit, and Kelvin instantly. Free temperature converter with common reference points. Fast and easy to use.

Length Converter

Convert between meters, feet, inches, kilometers, miles, and more. Free length converter with 9 units and instant results. Perfect for construction, travel, and science.

Weight Converter

Convert between kilograms, pounds, ounces, grams, stones, and more. Free weight converter with 7 units and instant results. Great for cooking, fitness, and shipping.

Time Zone Converter

Convert time between world time zones instantly. Free time zone converter with 27 zones, date picker, and popular city quick view. Schedule meetings across the globe.

Unit Converters

Instantly convert between hundreds of units across 8 categories. Every converter runs in your browser with no signup required.

Length

Weight

Temperature

Volume

Area

Speed

Digital Storage

Time

Frequently Asked Questions

How precise are the unit conversion results?

Conversions use internationally standardized conversion factors and are accurate to multiple decimal places. Results are suitable for engineering, cooking, travel, and academic use.

Which unit conversions are available?

We cover length (cm, inches, feet, meters), weight (kg, lbs, oz), temperature (Celsius, Fahrenheit, Kelvin), data size (bytes, KB, MB, GB), speed, and more. New converters are added regularly.

Can I convert between multiple units at once?

Most converters show the result for one target unit at a time. Enter your value, select the source and target units, and get the result instantly.