Base64 Decode

Decode Base64 back to text — accepts both alphabets and any line wrapping automatically.

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Base64

Decoded text

Output appears here as you type.

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About the Base64 Decode

Decoding turns a Base64 string back into the bytes it represents, interpreted as UTF-8 text. If the result looks like mojibake rather than readable characters, the original data was probably not text at all — an image or a compressed blob will decode to bytes that have no sensible string form.

Two things commonly break a decode. Padding matters: a truncated string missing its trailing `=` characters may fail outright. And base64url, used in JWTs and URLs, substitutes `-` and `_` for `+` and `/`, so a token pasted here needs those swapped back or a decoder that accepts both alphabets.

Frequently asked questions

Do I need to know whether my Base64 is URL-safe?

No. The decoder normalises - and _ back to + and /, strips whitespace and line breaks, and restores missing = padding automatically. Both alphabets and any wrapping just work.

Why do I get "not valid UTF-8 text"?

Because the Base64 decoded successfully but the resulting bytes are not text — you have binary data such as an image, PDF or compressed archive. That is a successful decode of non-text content. Use the Base64 to Image tool if it is an image.

What makes Base64 invalid?

Characters outside the alphabet (A–Z, a–z, 0–9, +, /, = or the URL-safe variants), or a length that cannot be padded to a multiple of four. The most common cause is a truncated copy-paste that cut the string short.