Base64 Encoder & Decoder, Free Online Tool for Developers

Base64 encoding is everywhere in web development, from embedding images in CSS to handling API authentication tokens. But manually encoding and decoding is tedious and error-prone. Our free Base64 Encoder/Decoder makes it instant.

The tool operates in two modes: Text and Image. In text mode, paste any string and encode it to Base64, or paste a Base64 string and decode it back to plain text. The auto-detect feature figures out which direction you need. In image mode, upload or drag-and-drop an image to get its Base64 string, data URI, and a ready-to-use <img> tag.

It's an essential tool for developers working with APIs that use Base64 authentication, front-end engineers embedding small images as data URIs in CSS, email developers encoding inline images, and anyone debugging Base64-encoded data in logs or payloads.

To use it: switch to the Text or Image tab. For text, paste your input and click Encode or Decode (or let auto-detect handle it). For images, drop a file into the upload zone. The encoded output appears instantly with one-click copy for each format, raw Base64, data URI, and HTML img tag.

When to use Base64 for images: data URIs are great for tiny images (icons, 1x1 tracking pixels, simple SVGs) where the overhead of an HTTP request exceeds the size of the encoded image. For anything over ~2KB, a regular image file with proper caching will perform better.

Related tools that complement this one: our JSON Formatter for cleaning up API responses, our Regex Tester for extracting data from strings, and our HTML/CSS/JS Minifier for optimising the final output.

No server-side processing, no data retention, no sign-up. Your sensitive data stays in your browser. The tool is fast, private, and handles both small snippets and large text blocks.