Base64 encoder and decoder

Turn text or a file into Base64, or decode Base64 back into readable text.

Encode Decode

Text to encode

URL-safe (Base64URL, no padding)

Result

What it does

Base64 writes any data, text or binary, using only 64 safe characters, so it can travel through JSON, URLs, email and config files. Encode text or a whole file, or decode a Base64 string back. Text is handled as UTF-8, so accents, Arabic, Chinese and emoji come back exactly, which a plain btoa() call in JavaScript can’t do. The decoder accepts standard and URL-safe Base64, with or without padding or line breaks, and if the decoded data is a file such as a PNG or PDF, it recognises it and lets you download it.

How to use it

How it works

Choose “Encode” or “Decode”.
Type or paste your text. The Base64 result appears as you type, and any problem is pointed out with its position.
When encoding, tick “URL-safe” for Base64URL (- and _ instead of + and /, without padding), as used in JWTs and URLs. When decoding, both kinds are detected automatically.
Copy the result, download it, or click “Decode this” / “Encode this” to convert it back.

Common uses

Reading a Base64 value from an API response, a Kubernetes secret or an email header
Encoding credentials for an HTTP Basic Authorization header (user:password)
Turning a small file into text to embed it in JSON or a config file

Tips

Base64 isn’t encryption: anyone can decode it. Don’t use it to hide passwords or keys.
Encoded data is about a third larger than the original: every 3 bytes become 4 characters.
For images in HTML or CSS, Image to Base64 gives you a ready-made data URI, img tag or CSS rule.

Questions

Why does my decoded text look garbled?

The original was probably encoded from a different character set than UTF-8, such as Windows-1252, or the data was a file rather than text. If it’s a known file type, the tool offers it as a download instead.

What’s the difference between Base64 and Base64URL?

Base64URL replaces + with - and / with _, and usually drops the = padding, so the result can sit in a URL or file name without escaping. JWTs use it. The decoder reads both.

Is there a size limit?

Text of several megabytes converts instantly. Files up to 10 MB can be encoded; beyond that the Base64 text is too long to handle comfortably in a text box.

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