Encode and decode Base64 text or files online, including URL-safe Base64 and MIME line wrapping, entirely in your browser.
Base64
is a way to represent arbitrary binary data using only 64 printable ASCII characters (A–Z,
a–z,
0–9,
+
and
/
). This Base64 encoder and decoder groups the input into 3-byte chunks and re-encodes each as four characters, padding the final group with
=
. It exists so binary can travel safely through text-only channels — email bodies, JSON, data URIs, HTTP headers.
Encoding is
not
encryption. Base64 is fully reversible by anyone, with no key involved — it adds zero secrecy and grows the payload by about a third. The
URL-safe
variant swaps
+//
for
-/_
and usually drops padding, so the value survives inside URLs and filenames. Everything here runs in your browser; the text and files you convert never leave your machine.
No. Base64 encoding and decoding run entirely client-side using the browser engine. Files are read locally with the FileReader API and are not sent to a server.
No. Base64 is encoding, not encryption. There is no key and anyone can decode it instantly, so never use Base64 to hide passwords, API keys or private data.
Standard Base64 uses + and /, which can be awkward in URLs and filenames. URL-safe Base64 substitutes - and _ and often omits = padding. This decoder accepts standard and URL-safe variants.
The input may contain a non-Base64 character, be truncated, or have invalid padding. Whitespace and line breaks are ignored automatically; if decoded bytes are not UTF-8 text, download the raw bytes instead.