About this tool
Convert UTF-8 text or files to Base64, Base64URL, or data URLs, and decode them without uploading the source.
How to use it
- Choose Encode or Decode and the source format.
- Enter text or explicitly choose a file.
- Copy text output or download decoded bytes after reviewing the result.
Formats
- Standard Base64 uses the + and / alphabet with canonical padding.
- Base64URL uses - and _, and this encoder omits padding. The decoder accepts either alphabet and missing padding.
Data URLs
- Text data URLs use text/plain;charset=utf-8; files use their reported MIME type or application/octet-stream.
- Data URLs always use padded Standard Base64. Non-Base64 and malformed data URLs are rejected.
Files and safety
- Files and text are processed only in this browser and are not retained after reload.
- Binary output is never rendered as active content. Downloads happen only when you choose Download.
Limits
- Text and file inputs are limited to 10 MiB of source bytes. Decoded output is also limited to 10 MiB.
- Only valid UTF-8 receives a text preview; other byte sequences remain binary.
Frequently asked questions
Is Base64 encryption?
No. Base64 is a reversible binary-to-text encoding and provides no confidentiality or authenticity.