Base64 encoder and decoder
Encode text or a file (up to 4 MiB) to Base64, standard or URL-safe, and decode Base64 back to text or a downloadable file.
- Runs in your browser
- No upload
- Result stays on your device
Privacy & limitsRuns in your browser. Nothing is uploaded.
Input content stays in this tab; Refentra does not upload or store it. Optional aggregate action counts are sent only with your usage consent. Clear the workspace when finished.
Supported profile: RFC 4648: UTF-8 text or file bytes; standard/URL-safe; file ≤4 MiB; binary download.
Maximum text: 200,000 UTF-16 units; parser limits can be smaller. Worker time limit: 15 seconds (regex 1.5 seconds).
Check the input and the result
- Prepare and choose the operation
Choose encode or decode, and the standard or URL-safe alphabet. The text is interpreted as UTF-8.
- Check a concrete example
Use this sample and compare the indicated result: Hello → SGVsbG8= → Hello; ✓ UTF-8 → 4pyT
- Check the output before you reuse it
Run a known sample through and back with the same alphabet. URL-safe base64 uses -/_ instead of +/ and may leave out padding.
Answers for this task
Does Base 64 protect a secret?
No. It is a reversible representation, not encryption. Anyone who has the encoded text can decode it.
What should I check if the input fails?
Check the alphabet and the padding. Binary bytes that are not valid UTF-8 can't be decoded as text here.
Where does this tool stop?
This text codec is limited to 200,000 UTF-16 input units. It is not a tool for extracting arbitrary binary files, and it doesn't authenticate the format.