When the format is the problem, not the content
A converter earns its keep when the thing you have is perfectly good, just in a shape the next step will not accept. An image an older app cannot open. Data stuck in a spreadsheet that a developer needs as JSON. Text that gets mangled travelling inside a URL. These tools change the shape without asking you to rebuild the content. They run in your browser, they are free, and there is no account to create.
Which converter should you use?
For images, start with the direction you are travelling. WebP files are smaller than the older formats, but not every app opens them happily. If a WebP image will not open where you need it, convert it back with WebP to JPG for maximum compatibility or WebP to PNG when you need transparency — transparency is the deciding factor. Going the other way, JPG to WebP to slim down website photos and PNG to WebP for smaller web graphics are the website-speed jobs. Unsure which pair you need? Start with the WebP Converter.
Between the two older formats, the rule is short. Use PNG to JPG to shrink a photograph when a PNG photo is bigger than it needs to be and has no transparency to lose. Use JPG to PNG when transparency or crisp edges matter for graphics and screenshots. And PNG to PDF to send images as one document covers screenshots that need to be emailed as one file.
For data, the pair people use most is JSON to CSV to open API data in a spreadsheet and its reverse, CSV to JSON to feed spreadsheet rows into code. CSV suits rows a human will read. JSON suits nested data a program will read.
Encoding, explained without the jargon
Two tools solve ordinary problems. The Base64 Encoder and Decoder for embedding data as text turns binary data into plain characters so it can travel as text. Remember the cost: Base64 makes data roughly a third bigger, so it is a transport trick, not a compression trick. The URL Encoder and Decoder for safe links fixes spaces and symbols that break a web address, converting them into a form browsers accept — and back again when you need to read what a link says.
The helpers developers reach for
Four smaller tools round out this page. The Markdown to HTML converter for web publishing turns documentation into markup a web page can use. The Color Picker and Converter for HEX and RGB values gives you a colour in the format your code expects. The QR Code Generator for links and text makes a scannable code. And the Regex Tester to check a pattern before you ship it lets you test a pattern live instead of guessing.
3D Printing & Hardware Manufacturing
For makers and engineers, the STL to GCODE Converter for 3D printing translates 3D mesh files into printable machine instructions (G-code) directly in your browser with zero file uploads. For a step-by-step walkthrough on setting layer heights, infill density, and nozzle temperatures, explore our comprehensive guide on how to convert STL to GCODE online.
A typical chain: convert a CSV export with CSV to JSON, check the result, then encode anything that has to travel inside a link. Open the result before you send it on.