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Base64 encoder and decoder

Encode text to Base64 or decode it back, entirely in your browser.

How it works

Base64 represents binary data using 64 printable ASCII characters, so it can travel through systems that only handle text — email attachments, data URIs, JSON payloads, HTTP headers.

It works by taking three bytes at a time (24 bits) and re-splitting them into four 6-bit groups, each mapped to a character from A–Z, a–z, 0–9, + and /. Because three bytes become four characters, Base64 data is always about 33% larger than the original. When the input length is not a multiple of three, the output is padded with one or two = signs.

Base64 is an encoding, not encryption. It provides no security whatsoever — anyone can decode it instantly, as this page demonstrates. Encoding a password or key in Base64 hides it from casual reading and from nothing else.

This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.

Common questions

Is Base64 encryption?
No. It is a reversible encoding with no key and no secret. Anyone can decode it, so it provides no security at all.
Why does Base64 make files bigger?
Every three bytes of input become four characters of output, so the result is roughly 33% larger, plus padding.
What do the equals signs at the end mean?
Padding. Base64 works in three-byte blocks, so when the input does not divide evenly, one or two = characters mark how many bytes were missing from the final block.

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