How to use the Base64 encoder
- Type or paste your text into the box.
- Click Encode to convert it to a Base64 string, or Decode to turn a Base64 string back into readable text.
- The result appears below with a label telling you which conversion was applied.
- Copy the result and use it wherever you need it — an API header, a data URL, or a config file.
What Base64 actually is
Base64 is a way of representing binary data using only 64 safe, printable characters — the letters A–Z, a–z, the digits 0–9, and the plus and slash symbols (with equals signs as padding). Because the output is plain text, it can travel through systems that only accept text, such as email, JSON payloads, and URLs, without being corrupted.
It is important to understand that Base64 is an encoding, not encryption. It does not hide or protect data — anyone can decode it. Its purpose is transport and compatibility, not security.
UTF-8 support matters
Many quick Base64 snippets you find online use the browser's btoa and atob functions directly. Those functions only work with Latin-1 text and will fail or corrupt anything outside that range — including accented letters, emoji, and characters from non-Latin scripts. This tool wraps those functions with a UTF-8 conversion step, so text in any language round-trips correctly: encode it, then decode it, and you get back exactly what you started with.
About the size of Base64 output
Base64 always produces output that is larger than the original input. Every three bytes of binary data become four Base64 characters, which works out to roughly a 33% increase in size. That overhead is the price of the safe, printable character set. When you are encoding something for transport rather than storage, the modest size increase is almost always worth the guarantee that the data will arrive intact through systems that only handle text.
Common uses
- Embedding small images in HTML or CSS as
data:URLs. - Sending credentials or tokens in HTTP Basic Authorization headers.
- Passing binary-safe text through JSON APIs or query strings.
- Inspecting the contents of a Base64 string you received from another system.