Base64 Encoder / Decoder
Encode and decode text in Base64. UTF-8 safe. Supports file → Base64 (up to 10 MB). 100% local.
- 100% local · no upload
Frequently asked questions
What is Base64 used for?
Embedding binary data (images, files) in text-only contexts (email, JSON, URLs, HTML data: URIs). Also auth headers (Basic auth) and JWT.
Why does the output look 33% larger?
Base64 encodes 3 bytes into 4 characters — overhead of 33%. That's the cost of being ASCII-safe.
Is it encryption?
No. Base64 is encoding, not encryption. Anyone can decode it instantly. Don't use it to "hide" sensitive data.
Does file encoding upload to a server?
No — files are read locally via FileReader API and never leave your browser.
What's the file size limit?
10 MB practical limit. Larger files crash the browser tab on encode (the entire result lives in memory as a string).