Base64 Decoder
Paste a Base64 string and see the decoded text as you type. Decoding happens in your browser.
Input
Base64 · decoded text
DecodedPaste Base64 in the input panel to decode it.
Base64 maps every 3 bytes onto 4 ASCII characters so binary data survives text-only channels — data URIs, JSON, email. It's an encoding, not encryption: anyone can reverse it. This tool round-trips full UTF-8, so accented and non-Latin text encode and decode cleanly.
- Ratio
- 3 : 4
- Charset
- A–Z 0–9 + /
Related tools
Guides
Paste a Base64 string and this Base64 decoder shows the original text right away. There's no Decode button; the output updates as you type.
It's forgiving about input. Spaces and line breaks are stripped, the URL-safe alphabet (- and _ in place of + and /) is accepted, and missing = padding is added back. The decoded bytes do have to be valid UTF-8 text. Paste the Base64 of an image or a zip file and you'll get an error message instead of garbage.
The text you paste isn't sent to a server. Decoding runs in your browser, which is worth knowing when the string holds a token or a password.
What is Base64 decoding?
Base64 writes every 3 bytes of data as 4 printable characters. Decoding runs that in reverse. You'll run into it when:
- Reading the payload segment of a JWT
- Checking an HTTP Basic auth header (the part after "Basic ")
- Reading MIME parts in a raw email
- Inspecting a value an API returned as Base64
How to use the Base64 decoder
- Paste your Base64 string into the input box.
- Read the decoded text in the output panel. It updates as you type.
- If the input isn't valid Base64, or the bytes aren't UTF-8 text, you'll see an error instead.
- Click Copy result to grab the text.
Example outputs
A few strings and what they decode to:
- aGVsbG8= → hello
- aGVsbG8 → hello (the padding is optional here)
- Y2Fmw6k= → café (the é takes two bytes in UTF-8)
Frequently asked questions
Is Base64 decoding the same as decryption?
No. Base64 has no key, so anyone can reverse it. If a value only looks secret because it's in Base64, it isn't secret.
Why do I get an error for a string that looks fine?
Either it contains characters outside the Base64 alphabet, or it decodes to bytes that aren't UTF-8 text, such as an image or compressed data. This tool only shows text output.
Can I decode URL-safe Base64 or a JWT?
Yes. - and _ are read as + and /, and missing padding is filled in. Paste one segment of the JWT at a time, not the whole token with its dots.
Is this Base64 decoder free?
Yes, and there's no sign-up.
Built and maintained by Bipul Kumar. Found a wrong number or a broken result? Tell me and I'll fix it.