Base64 Decode
Decode Base64 back to plain text.
About Base64 Decode
Base64 Decode turns Base64 back into readable text. Testers reach for it constantly: peeking inside JWT segments, decoding Basic auth headers found in logs, unpacking data URIs, or inspecting encoded fields in API payloads and message queues.
Decoding is instant and local. Because the tool decodes as UTF-8, international text and emoji round-trip correctly with the matching encoder.
How to use
- Paste the Base64 string into the input box.
- The decoded text appears immediately; invalid Base64 shows an error instead.
- Copy the decoded result, or fix the input if padding or characters are off.
Frequently asked questions
Why does my string fail to decode?
Common causes: missing padding (= characters), URL-safe Base64 variants using - and _ instead of + and /, whitespace or line breaks pasted mid-string, or the string simply not being Base64.
What is the difference between Base64 and Base64URL?
Base64URL replaces + with - and / with _ and usually drops padding so the value is safe in URLs and JWTs. If a JWT segment fails here, that variant is why — the JWT Decoder tool handles it natively.
Is decoded output always text?
Base64 can carry binary data (images, files). If the decoded result looks like garbage characters, the original content was probably binary rather than text.