Base64 Converter
About the Base64 Converter
Encode plain text to Base64 or decode a Base64 string back to text, with the result updating as you type. It is built for developers working with data URIs, HTTP Basic authentication headers, email attachments and APIs that expect Base64 payloads.
How to use it
- 1 Choose Encode or Decode.
- 2 Type or paste your text into the input pane, up to 100,000 characters.
- 3 Read the result in the output pane; it updates as you type.
- 4 Click Copy to put the result on your clipboard, or Clear to start again.
Frequently asked questions
Base64 represents binary data with 64 printable characters: A–Z, a–z, 0–9, + and /, with = as padding. Every 3 bytes become 4 characters, so encoded data is about 33% larger than the original.
No. Base64 is an encoding, not encryption. Anyone can decode it without a key, so never rely on it to hide passwords, tokens or other secrets.
The decoder is strict: any character outside the standard Base64 alphabet makes it fail. URL-safe Base64, which uses - and _ instead of + and /, is rejected, so swap those characters back first. Spaces and line breaks are ignored.
If the decoded bytes are not valid UTF-8, for example an image or another binary file, the tool says it decoded successfully and how many bytes of binary data it found, instead of printing unreadable characters.
Yes. Text is encoded as UTF-8 bytes, so accented letters, non-Latin scripts and emoji survive a round trip from Encode to Decode unchanged.