MMaxTools

Base64 Decoder

Decode Base64 back to readable text — UTF-8 safe, instant and private.

The Base64 Decoder turns Base64 back into the text it encodes. Paste an encoded value — from an email attachment header, an API response, a data URI, or a config value — and the tool decodes it instantly with full UTF-8 support, so emoji, accents and non-Latin scripts come back intact.

The decoder validates its input first: it rejects values with wrong length or illegal characters instead of returning garbage, and it detects when the decoded bytes are not text at all. If you decode something that turns out to be a binary file or image, the tool tells you rather than showing nonsense.

Decoding runs locally in your browser — even sensitive tokens and internal values never leave your device. This page is the exact reverse of the Base64 Encoder, so round trips stay lossless.

Paste Base64 data to decode it as text. Handles UTF-8 (emoji, accents and non-Latin scripts) correctly.

How to use the Base64 Decoder

  1. Paste the Base64 (or Base64url) value to decode.
  2. Read the decoded text — or the notice that the data is binary.
  3. Copy the result if you need it elsewhere.
  4. Fix invalid input using the error message guidance.
  5. That's it — decoding is instant and offline.

Frequently asked questions

Why does my decoded text contain strange characters?

The original bytes may not be UTF-8 text — they could be an image, PDF or other binary data. The decoder detects invalid UTF-8 and tells you, instead of printing replacement characters.

Can it decode Base64url (JWT segments)?

Yes. The - and _ characters and missing padding are handled automatically, so JWT payload segments and other Base64url values decode without manual conversion.

Is decoding private?

Completely — the conversion happens in your browser with no network requests. You can safely decode access tokens and configuration secrets here.