Base64 encode / decode
Convert text to and from Base64, instantly in your browser.
This tool lets you Base64 encode and decode text in both directions without installing anything. Base64 represents binary or text data using a 64-character alphabet so it can travel safely through systems that only handle plain text, such as email headers, JSON payloads, and data URIs. Paste your content, pick a direction, and the converted result appears immediately — encoding expands data by roughly a third, while decoding restores the original bytes. The conversion runs entirely in your browser, so sensitive strings stay on your device.
Frequently asked questions
Is Base64 a form of encryption?
No. It is reversible encoding with no secret key, so anyone can decode it. Never treat Base64 as a way to hide sensitive data.
Why is my encoded text longer than the original?
Base64 uses four characters to represent every three bytes, so output is about 33 percent larger than the input.
Can it handle non-English characters?
Yes. Text is treated as UTF-8 before encoding, so accented letters and other Unicode characters round-trip correctly.
Is my data uploaded anywhere?
No. Encoding and decoding run entirely in your browser; nothing is sent to a server.
What's the difference between Base64 and Base64URL?
Base64URL replaces the + and / characters with - and _ and usually drops the trailing = padding, so the result is safe to put in URLs and filenames. JWTs use the URL-safe variant.
Why won't my Base64 string decode?
It's usually invalid characters, missing = padding, or a URL-safe string being decoded as standard Base64 (or vice versa). Stripping stray whitespace and matching the right variant normally fixes it.
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