Free Online Converter Tools

Free Online Converter Tools That Just Work

ToolRux offers 20 free online converter tools for units, currencies, time zones, and data formats. Whether you need to convert kilometers to miles, transform CSV to JSON, or switch between time zones — every conversion happens instantly in your browser with zero data sent to any server.

Unit & Measurement Converters

Convert accurately between hundreds of units across multiple measurement systems:

• Unit Converter — Convert between length, weight, volume, area, speed, and more. Supports metric, imperial, and specialty units.
• Length Converter — Convert between meters, feet, inches, centimeters, kilometers, miles, yards, and more.
• Temperature Converter — Convert between Celsius, Fahrenheit, and Kelvin with real-time results.
• Data Size Converter — Convert between bytes, kilobytes, megabytes, gigabytes, terabytes, and more.

Currency & Time Converters

• Currency Converter — Convert between 150+ world currencies with real-time exchange rates. Supports USD, EUR, GBP, INR, JPY, and more.
• Time Zone Converter — Convert times between any two time zones worldwide. Accounts for daylight saving time automatically.

Data Format Converters

Transform between popular data formats for development and data processing:

• CSV to JSON Converter — Convert CSV data to JSON and vice versa. Supports custom delimiters, header detection, and RFC 4180 parsing.
• YAML to JSON Converter — Convert YAML configuration files to JSON and back. Handles nested objects, arrays, block scalars, and inline collections.
• Markdown to HTML Converter — Convert Markdown to HTML with live preview. Supports GFM tables, code blocks, task lists, and more.
• XML to JSON Converter — Convert XML to JSON with attribute handling, namespace support, and auto-array grouping for repeated elements.
• Image Format Converter — Convert images between PNG, JPG, and WebP formats with quality control. All processing happens locally in your browser.

Weight, Speed, Area & Energy Converters

• Weight Converter — Convert between kilograms, pounds, ounces, stones, grams, and more with instant results.
• Speed Converter — Convert between km/h, mph, m/s, knots, and other speed units.
• Area Converter — Convert between square meters, acres, hectares, square feet, and other area units.
• Energy & Power Converter — Convert between joules, calories, kilowatt-hours, BTUs, electron-volts, and more.

Additional Format & Data Converters

• Image to PDF Converter — Combine multiple images into a single PDF file with page size, orientation, and quality controls. All processing in your browser.
• Color Format Converter — Convert colors between HEX, RGB, HSL, and other formats with live preview.
• Number to Words Converter — Convert any number to its written English word form — great for checks, invoices, and legal documents.
• JSON to CSV Converter — Convert JSON arrays to CSV spreadsheet format and vice versa with header detection.
• HTML to Markdown Converter — Transform HTML markup into clean Markdown and back. Supports tables, lists, code blocks, and more.

Need calculations instead? Check out our Calculators. For developer-specific tools, see Developer Tools.

Why Use ToolRux Converters?

• 100% Free — Every converter is completely free with no sign-up required.
• Privacy First — All conversions happen in your browser. Your data never leaves your device.
• Instant Results — Real-time conversion as you type — no loading, no waiting.
• Bidirectional — Convert in both directions with a single click. CSV to JSON and JSON to CSV, Markdown to HTML and HTML to Markdown.
• File Upload & Download — Upload files directly and download converted output in the correct format.
• Mobile Friendly — Fully responsive design works on phones, tablets, and desktops.
• Dark Mode — Easy on the eyes with automatic dark mode support.

Frequently Asked Questions

Are these converter tools really free?

Yes — every converter on ToolRux is completely free to use with no registration required.

Is my data safe?

Absolutely. All conversions happen entirely in your browser using client-side JavaScript. No data is uploaded to any server. Your files, text, and images stay on your device. See our privacy policy for details.

Can I upload files for conversion?

Yes. Text-based converters (CSV, YAML, XML, Markdown) support file upload — just click the "Upload" button and select your file. The Image Format Converter supports drag-and-drop as well.

What file formats are supported?

We support CSV, JSON, YAML, XML, HTML, Markdown, and image formats (PNG, JPG, WebP, GIF, BMP, SVG). Each converter handles the specific format pair it's designed for.

Can I use these tools on my phone?

Yes. All converters are fully responsive and work on any modern browser — Chrome, Safari, Firefox, Edge — on mobile phones, tablets, and desktop computers.

How accurate are the unit conversions?

Our unit converters use industry-standard conversion factors with high precision. Currency conversions use real-time exchange rates from reliable data sources.

Can I convert in both directions?

Yes. All text-format converters (CSV↔JSON, YAML↔JSON, Markdown↔HTML, XML↔JSON) support bidirectional conversion. Just toggle the direction and the tool adapts instantly.

What happens to image quality during conversion?

For lossless formats like PNG, quality is preserved perfectly. For lossy formats like JPG and WebP, you can adjust the quality slider (10-100%) to balance file size and visual quality. A side-by-side preview lets you compare before downloading.

Do I need to install any software?

No. Everything runs directly in your web browser — no downloads, extensions, or plugins needed.

Can I download the converted output?

Yes. Every converter includes a "Download" button that saves the output in the correct file format (.json, .csv, .yaml, .xml, .html, .md, or image files).