Base64 decoder

How to decode Base64

Paste the Base64 string into the input pane and click Convert. The decoder strips spaces and line breaks, turns the characters back into bytes and reads those bytes as UTF-8 text, so accented letters, emoji and non-Latin scripts come out correctly. Copy the result from the output pane.

Formats it accepts

Standard Base64 uses A to Z, a to z, 0 to 9, + and /, with = padding at the end. URL-safe Base64, used in JWTs and many web APIs, swaps + and / for - and _ and often drops the padding. Both decode here without changes. Text copied from an email or a PEM-style block can contain line breaks every 64 or 76 characters, and those are ignored. A data: URL such as data:text/plain;base64,... works too, because the prefix is removed before decoding.

When the result isn't text

Base64 often carries files rather than words: images in data URLs, PDF attachments, ZIP archives or encryption keys. Those bytes can't be shown as text, so instead of printing unreadable characters the decoder tells you the data is binary and, for PNG, JPEG, GIF, PDF and ZIP, which kind of file it is. To save a Base64 image as a file, use the Decode tab of Image to Base64.

Common things to decode

Developers decode Base64 to read the user:password pair in an HTTP Basic Authorization header, inspect a configuration value stored in a Kubernetes secret or an environment variable, check what an API returned in a Base64 field, or read the header and payload of a token. For JSON Web Tokens the JWT decoder is quicker, because it splits the token and formats each part.

Before you start

Input: TXT. Output: Text. The settings appear before anything runs, so you can check them first. Your original file is never changed.

The value you enter is processed in your browser. Still test the output where it will be used. Clean formatting does not prove the data is safe or correct.

Keep the original until you have opened and checked the result. The work happens in this browser tab, so the size you can handle depends on your device's memory, your browser and the file itself.

How to use the Base64 decoder

1. Paste the Base64 string you want to decode.
2. Click Convert to turn it back into text.
3. Copy the decoded text.