Base64 Encoder — Free, Runs in Your Browser
Turn text into Base64, with the alphabet your target expects.
Runs on your device What you paste is processed by your own browser. It is never sent to a server, and it is not stored anywhere after you leave the page.
Short answer
Text can be encoded to Base64 for free in a web browser with no upload. The text is first encoded as UTF-8 bytes and those bytes are then written in the Base64 alphabet, which is what makes non-English characters and emoji work correctly. A URL-safe variant is available, replacing plus and slash with hyphen and underscore and dropping the padding, so the result can be dropped into a query string or a filename unchanged.
At a glance
| Accepts | Any text |
|---|---|
| Produces | Base64 (standard or URL-safe) |
| Processing | In your browser |
| Price | Free, no limits |
| Account | Not required |
Base64 is not encryption and is not intended to be: it is a way of writing arbitrary bytes using 64 characters that survive systems built for text. That is why it turns up in data URIs, in HTTP Basic credentials, in email attachments and in the header and payload of every JWT. Anyone can decode it, so it hides nothing.
The UTF-8 step is where most hand-rolled implementations go wrong. The browser's own btoa refuses anything above U+00FF, so a naive encoder throws on the first accented letter or Chinese character; this one encodes the text's actual bytes first, which is what every other Base64 implementation does and why the result round-trips through any language.
How to use it
- 1
Paste your text
Anything at all — a sentence, a JSON payload, a certificate body.
- 2
Pick the alphabet
Standard for almost everything. URL-safe when the result goes into a URL, a filename or a JWT.
- 3
Convert
The encoded string appears immediately. Nothing is sent anywhere to produce it.
- 4
Copy the result
Copy puts it on the clipboard, or download it as a text file.
Frequently asked questions
Does Base64 encrypt my text?
No, and it is important not to treat it that way. Base64 is a reversible encoding with no key — anyone who has the string can read the original. Use it to move bytes through a text channel, never to hide them.
Does it handle emoji and Chinese characters?
Yes. The text is converted to UTF-8 bytes before encoding, so every character survives the round trip. Encoders built directly on btoa fail on exactly these inputs.
When should I choose URL-safe?
When the result will appear in a URL, a query parameter, a filename or a JWT. Standard Base64 uses + and /, which have their own meaning in a URL, and = padding, which often needs escaping. The URL-safe alphabet avoids all three.
How much larger does the text get?
About a third. Base64 writes every three bytes as four characters, so the encoded form is roughly 133% of the original size, plus padding.