Base64 Encode / Decode
Encode text to Base64 or decode Base64 back to text — instantly, in your browser.
Type some text on the left to encode it.
Qu’est-ce que Base64 Encode / Decode ?
Base64 is an encoding scheme that represents binary or text data using only 64 printable ASCII characters (A-Z, a-z, 0-9, +, and /), with = padding so the output length is a multiple of four. It is neither encryption nor compression — it provides no confidentiality and the output is usually slightly larger than the input. It is commonly used to embed images in CSS and HTML data URIs, attach binary files inside email messages, and carry binary data through text-only channels such as JSON or URLs. The same input always produces the same output, and decoding reverses it exactly as long as the character set and padding are intact.
Comment utiliser Base64 Encode / Decode
- Choose "Encode" to convert plain text to Base64, or "Decode" to convert Base64 back to text.
- Type or paste your input into the box.
- The result updates instantly below — no button click needed.
- Click "Copy" to copy the result to your clipboard.
Exemples
Encode
Entrée : hello world
Sortie : aGVsbG8gd29ybGQ=
Decode
Entrée : aGVsbG8gd29ybGQ=
Sortie : hello world
Encode with unicode
Entrée : café ☕
Sortie : Y2Fmw6kg4piV
Erreurs courantes
- Assuming Base64 is a form of encryption or compression — it's neither, and the output is often larger than the input.
- Forgetting the '=' padding characters when manually constructing or editing a Base64 string.
- Including line breaks in the input, which some Base64 variants (like MIME) insert but strict decoders reject.
- Mixing up standard Base64 with the URL-safe variant (which uses '-' and '_' instead of '+' and '/').
Pourquoi utiliser cet outil
- Runs fully client-side, so nothing you encode or decode leaves your browser.
- Correctly handles Unicode input, unlike a naive btoa()/atob() call in the browser console.
- Combines encode and decode in a single tool with instant, no-click feedback.
- No file size restrictions beyond what your browser's memory can comfortably handle.