Base64 Decoder
Decode Base64 back into readable text, with clear errors for malformed input.
Decoding happens locally in your browser. Your data is never uploaded.
What is base64 decoder?
Paste any standard Base64 string and get the original text back, including Unicode content encoded as UTF-8. Invalid characters or broken padding are reported with a clear explanation instead of a silent failure.
Like the rest of Uttir, decoding runs entirely in your browser — handy for inspecting tokens, data URLs, and encoded payloads that you would rather not paste into a random website.
How to use it
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Paste Base64
Whitespace-free standard Base64 with optional = padding.
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Read or copy the result
The decoded text appears live on the right.
Examples
Round trip
Decoding the encoder’s example returns the original text.
aGVsbG8gd29ybGQ=
Result: hello world