Base64 is an encoding, not encryption — anyone can decode it. Files and text are processed on your device only.
Text — encode / decode
File → Base64
Base64 → file
Encode text or files to Base64 and decode Base64 back — UTF-8 safe, with a URL-safe variant, file download and clear errors. Everything runs on your device.
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Encode text or files to Base64 and decode Base64 back — UTF-8 safe, with a URL-safe variant, file download and clear errors. Everything runs on your device.
The text "Asad ✓" encodes to QXNhZCDinJM= — note the checkmark survives the round trip, which naive encoders break. And a 90 KB logo becomes about 120 KB of Base64 text, ready to paste into an email template, a CSS file or a data URI.
Encoding follows RFC 4648: the input is read as bytes (text is converted to UTF-8 first, which is why symbols survive), grouped in threes and mapped onto the 64-character alphabet, with = padding rounding the output to a multiple of four. Decoding reverses the process and validates as it goes — misplaced padding or foreign characters produce a specific error message, not silent garbage. Files are read as bytes locally; nothing is uploaded anywhere.
No. Base64 simply re-represents bytes using printable characters; there is no key, and anyone can reverse it instantly — the decoder on this very page does it. Use Base64 for transport and embedding, never for secrecy.
Usually an encoding mismatch: if text contains anything beyond plain ASCII and a tool treats it as Latin-1 instead of UTF-8, multi-byte characters shatter. This tool treats text as UTF-8, the modern standard, so accents, scripts and emoji survive the round trip.
Standard Base64 uses + and /, which mean other things inside a URL. The URL-safe alphabet (RFC 4648 section 5) substitutes - and _ and usually omits the padding, so the value can travel inside links and filenames without escaping.
Comfortably a few megabytes on a desktop. The limit is your device’s memory, because the file, its Base64 (a third larger) and the copy buffer may all be held at once. For large media files, Base64 is rarely the right tool anyway.
The input was not valid Base64. Common causes: a truncated paste, a chunk missing from the middle, or leftover characters from a label or a quote. A data-URI prefix (data:image/png;base64,) is stripped automatically — so check the middle of the string for a missing piece.