Base64 Encoder/Decoder
Encode and decode UTF-8 text as Base64 in your browser
Accepted upload: .txt · max 5 MB. Encoding uses UTF-8 so Unicode and emoji are preserved.
Input
Plain text or Base64
Output
Encode or decode result
About this Base64 converter
Encode UTF-8 text to Base64 or decode Base64 back to text. The tool can auto-detect likely encoded input, swap directions, and accept .txt uploads up to 5 MB. Work happens in your browser with copy and download options.
How to use
- Paste text or upload a .txt file (5 MB max).
- Choose Encode or Decode, or use Swap to flip input and output.
- Rely on auto-detect hints when switching between plain and Base64-looking strings.
- Copy the result or download it when finished.
Encoding and decoding
Base64 represents binary data as ASCII-safe text. This tool treats input as UTF-8 text for encoding and attempts sensible decoding when the input looks like standard Base64. Invalid padding or characters will show a decode error rather than silent garbage.
Common uses
- Prepare small text payloads for APIs or data URLs.
- Inspect Base64 snippets from logs or configs.
- Quickly verify that emoji and non-Latin text round-trip through Base64.
Tips
- Decoding already accepts URL-safe Base64 (- and _) and normalizes padding when needed. If an API requires URL-safe output when encoding, convert + / characters after Encode.
- If decode fails, check for missing padding or extra whitespace on one line.
- Large files should stay under 5 MB; split bigger assets elsewhere.
Privacy
Encoding and decoding run locally. Your text and files are not uploaded to ToolsArk for conversion.
Limitations
- 5 MB upload cap; meant for text, not arbitrary binary file workflows.
- Auto-detect is a hint, not proof—always confirm direction before using secrets.
- Does not replace dedicated binary-to-Base64 tools for large media files.
Frequently asked questions
Common questions about the Base64 Encoder/Decoder.
How does Base64 Encoder/Decoder work?
Paste or upload text, then Encode or Decode. Encoding turns UTF-8 text into Base64. Decoding accepts standard Base64 and URL-safe Base64 (- and _) with padding fixed when needed.
Does my text leave my device?
No. Encoding and decoding run in your browser. ToolsArk does not upload your input to a server.
Can I decode binary Base64?
This tool expects the decoded bytes to be valid UTF-8 text. Binary payloads that are not UTF-8 text will fail. Use a dedicated binary/file tool if you need raw bytes.
What are the size limits?
Text input is capped around 1.5 million characters. File uploads accept .txt up to 5 MB.
What does the detection badge mean?
It is a heuristic hint (plain text, looks like Base64, or invalid Base64). Always use Encode or Decode explicitly — the badge does not change your text by itself.
Tags
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