Base64 Encoder/Decoder
Encode text or files to Base64 and decode Base64 strings back to their original form. Handles Unicode text and binary files with proper UTF-8 support.
Base64 encoding converts binary data to ASCII text using 64 printable characters, adding ~33% size overhead. It is commonly used in data URIs, JWT tokens, HTTP Basic Auth headers, and email attachments.
Frequently Asked Questions
What's the difference between standard and URL-safe Base64?
URL-safe Base64 replaces + with - and / with _ so the output is safe to use in URLs and filenames without encoding.
How much larger is Base64 output compared to the original?
Base64 encoding increases data size by approximately 33%. A 100-byte input produces a 136-byte output. This overhead is acceptable for small data like tokens, but avoid it for large binary files.
Is Base64 the same as encryption?
No. Base64 is encoding, not encryption. Encoded data can be decoded by anyone without a key. Never use Base64 to hide sensitive information.
Is my data sent to a server?
No. All encoding and decoding happens entirely in your browser using the JavaScript atob() and btoa() APIs. No data is transmitted anywhere.