Base64 Encoder / Decoder

Encode and decode Base64 text or files, including data URLs.

Mode

Input

URL-safe alphabet ( - and _ instead of + and / )

Wrap output at 76 characters

Output as a data: URL

Output

The result will appear here.

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About this tool

Base64 turns arbitrary bytes into 64 safe ASCII characters. It is not encryption and it hides nothing — its job is to let binary data travel through channels that only accept text: JSON fields, email bodies, HTTP headers, data URLs in CSS.

The cost is size. Every three bytes become four characters, so a Base64 payload is roughly a third larger than the original. That is why it belongs on small assets and API payloads rather than on large files.

How to use it

Choose a mode: text to Base64, Base64 to text, file to Base64, or Base64 to file.
Type, paste or upload. Data URLs are recognised automatically, and the MIME type is read from them.
Switch on the URL-safe alphabet when the result goes into a URL or a filename — it replaces + and / with - and _.
Copy the output, or download it when you decoded a file.

Examples

Text with non-ASCII characters

Encoding is done on UTF-8 bytes, so accented and Turkish characters round-trip correctly.

Merhaba Dünya

TWVyaGFiYSBEw7xueWE=

A data URL

Paste a full data: URL and the payload is decoded with its declared MIME type preserved.

data:text/plain;base64,VG9vbGl2YQ==

Utilerio

Common problems

Decoding produces unreadable characters.: The bytes are not UTF-8 text — they are probably a binary file. Switch to “Base64 to file” and download them instead.
“Invalid Base64” on a string that looks fine.: Check the length and the padding. Valid Base64 is a multiple of four characters, padded with = when it is not. A string copied out of a wrapped log is often truncated.
The value breaks when used in a URL.: Standard Base64 contains + and /, which have meaning in URLs. Turn on the URL-safe alphabet.