Free Online Converters — Units, Color, Currency & More
Convert between metric and imperial units, HEX/RGB/HSL colors, CSV and JSON data formats, binary and hexadecimal numbers, Roman numerals, and world currencies — all free, instant, and running entirely in your browser.
All Converter Tools
Unit Converter
Convert length, weight, temperature, speed, and more.
ConverterColor Converter
Convert between HEX, RGB, HSL, HSV, and CMYK.
ConverterBase64 Encode/Decode
Encode or decode Base64 strings and files.
ConverterCSV ↔ JSON Converter
Convert CSV to JSON or JSON to CSV instantly.
ConverterRoman Numeral Converter
Convert between Roman numerals and Arabic numbers.
ConverterNumber to Words
Convert numbers into English words for cheques and documents.
ConverterNumber Base Converter
Convert numbers between any base from 2 to 36 (binary, octal, hex, and more).
ConverterAbout Converter Tools
Conversion tools are essential for developers, designers, scientists, and anyone working across different systems and formats. Our converter collection covers the most common real-world conversion needs without requiring any account or software installation.
The Unit Converter handles length, weight, temperature, speed, area, volume, and digital data units — switching between metric and imperial systems instantly. The Color Converter supports HEX, RGB, HSL, HSV, and CMYK with a live color preview, making it a daily companion for web designers and front-end developers.
For data work, the CSV to JSON Converter and its reverse let you switch between spreadsheet and API-friendly formats in a single click. The Base64 Encode/Decode tool handles text and binary files, while the Binary/Hex/Octal Converter is indispensable for low-level programming tasks.
The Number to Words converter is useful for writing cheques and legal documents, while the Roman Numeral Converter handles numbers up to 3,999. The Currency Converter provides fast conversion between 30+ world currencies. All tools work offline once the page is loaded, and none of your data is ever sent to a server.
Frequently Asked Questions
How accurate are the unit conversions?
All unit conversions use exact or internationally standardised conversion factors (e.g., 1 inch = 25.4 mm exactly). Results are accurate to the precision of JavaScript's 64-bit floating-point arithmetic.
Are live exchange rates used for currency conversion?
The Currency Converter fetches rates from a public exchange rate API. Rates are indicative and may differ slightly from bank or institutional rates.
Does the unit converter support all measurement systems?
Yes. The Unit Converter supports metric (SI), imperial, and US customary units across length, mass, temperature, speed, area, volume, and digital storage categories.
Do the converters work offline?
Most converters work fully offline once the page is loaded, as all logic runs in JavaScript. The Currency Converter requires an internet connection to fetch current exchange rates.
Are the converters free to use?
Yes, all converters are completely free with no usage limits, no account required, and no watermarks.