Base64 Decode turns Base64 back into what it was: readable text, an image you can see, or a file you can download. Paste plain Base64, URL-safe Base64 or a complete data: URL. The tool looks at the decoded bytes to work out what they are, so you do not have to know in advance. Everything runs in your browser.
How to decode Base64
- Paste the Base64 text or data URL into the box. It is decoded straight away.
- If it is text, the decoded text appears below, read as UTF-8 so every language works.
- If it is an image, you see a preview, and can download it.
- If it is another file, such as a PDF or a ZIP, the status line tells you its type and size. Click Download.
What it recognises
| Type | Formats |
|---|---|
| Images | PNG, JPEG, GIF, WebP (with preview) |
| Documents | |
| Archives | ZIP, gzip |
| Fonts | WOFF, WOFF2, TTF |
| Text | UTF-8 text; other data is offered as a binary download |
The type comes from the first bytes of the decoded data, the “magic number” each file format starts with. For a data URL, the type written in the URL is used when the bytes are not recognised, for example for SVG images.
Where you meet Base64
- Email source: attachments and some message bodies are Base64 with line breaks every 76 characters. Paste the block to get the file back.
- API responses and JSON: files and images are often sent as Base64 strings. Use the JSON Formatter to find the field, then decode it here.
- HTML and CSS: inline images written as
data:image/...;base64,.... - JSON Web Tokens: the header and payload are URL-safe Base64. Paste one part at a time.
- Logs and configs: keys, certificates and binary blobs stored as text.
Errors and fixes
- “This is not Base64”: the text contains other characters. Remove quotes, a variable name or a trailing comma copied along with it.
- “The Base64 text is cut off”: part of the string is missing. Copy it again, all the way to the end.
- “Binary data”: the bytes are not text and not a recognised file type. Download them and open the file with the program it belongs to.
Need the other direction?
To turn text into Base64, switch to Encode text. To turn an image into Base64 or a data URL, see Image to Base64. Base64 is not encryption: anything encoded can be decoded here, so never use it to hide passwords.