Development
Base64 Encoder / Decoder
Encode text and files to Base64 or decode Base64 back – with URL-safe alphabet, data URIs for CSS and HTML, image preview, file type detection and the exact error position.
- Runs entirely in your browser
- No data upload
- No sign-up
- Free
Text
Base64
Hex view
Guide
How it works
- Choose the direction
Choose “Encode” to convert text or a file to Base64, or “Decode” to convert Base64 or a data URI back.
- Enter input
Type or paste text, drag a file into the field or open it via “Open file”. The result appears instantly.
- Adjust options
Choose the URL-safe alphabet for URLs and file names, omit padding or wrap lines for email (76) and certificates (64). For images, there are ready-made data URIs for CSS and HTML.
- Use the result
Copy the result, download it or swap input and output to cross-check.
FAQ
Frequently asked questions
What is Base64?
Base64 represents any data with just 64 easily transferable characters (A–Z, a–z, 0–9, + and /). This allows images, files or special characters to be safely embedded in emails, JSON, HTML or URLs. Every 3 bytes become 4 characters – so the data grows by about a third.
Is Base64 encryption?
No. Base64 is just an encoding and can be reversed by anyone without a key. It offers no protection for passwords or confidential data.
What does “URL-safe” mean?
The characters + and / have a special meaning in URLs and file names. The URL-safe variant (Base64url, RFC 4648) replaces them with - and _ and usually omits the padding = – for example in JSON Web Tokens (JWT). When decoding, the tool recognizes both variants automatically.
Why do special characters look different than in other tools?
Base64 encodes bytes, not characters. How an “ü” becomes bytes depends on the character set: in UTF-8 it is two bytes, in ISO-8859-1 one. If the character set does not match when decoding, characters like “ü” appear – then simply choose the other character set.
When is a data URI worthwhile?
For small graphics such as icons (up to about 2–4 KB), a data URI saves an additional request. For larger files, the disadvantages outweigh: about 33 % more data and no separate caching.
Are my files uploaded?
No. Everything – including opening files, the preview and the download – happens locally in your browser.