Base64 Decoder
Decode Base64-encoded strings back to plain text.
What Is Base64 Decoding?
Base64 decoding is the reverse of Base64 encoding — it takes a Base64 string and converts it back to the original text or binary data. This tool handles UTF-8 text correctly, even for emoji and non-Latin characters.
How to Spot a Base64 String
Base64 strings have a distinctive look:
They use only the characters A–Z, a–z, 0–9, +, and /. The string often ends with one or two = padding characters. The length is always a multiple of 4 (before any padding is stripped).
For example: SGVsbG8gV29ybGQ= decodes to Hello World.
Common Uses of Base64-Encoded Strings
Data URLs: The data after base64, in a data:image/png;base64,... URL is Base64-encoded binary image data.
HTTP Basic Auth: The Authorization: Basic ... header contains a Base64-encoded username:password string.
Email attachments: MIME-encoded attachments are Base64 strings you can paste here to inspect the raw content.
API tokens & secrets: Some services deliver credentials or payloads as Base64 strings that need decoding before use.
Invalid Input Errors
If the input contains characters outside the Base64 alphabet or has an incorrect length, the decoder will show an error. Whitespace and line breaks are automatically stripped before decoding, so you can safely paste multi-line Base64 here.
Need more encoding tools? Try the full Encode & Decode suite.