Encode a short UTF-8 message
Scenario: The text Hello is encoded.
Result: The Base64 output is SGVsbG8=.
The UTF-8 bytes for Hello are grouped into six-bit values and mapped to the Base64 alphabet, with padding added to complete the final group.
💻 Developer Tools
Base64 Encoder & Decoder
Encode or decode UTF-8 text with standard Base64 or URL-safe Base64URL.
Ready to use · Runs in your browser · No signup
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How to use the Base64 Encoder & Decoder
Convert UTF-8 text to standard Base64 or unpadded Base64URL, or decode the selected representation back to text locally.
Encode UTF-8 text as standard Base64 or unpadded Base64URL, and decode either selected form back to text. Base64 is a reversible binary-to-text representation, not encryption or password protection.
Input stays in the browser and is not sent to Fieldlet. Do not treat a formatting, encoding, test, or generated value as a substitute for security review.
- Choose Encode or Decode and select standard Base64 or URL-safe Base64URL.
- Paste the UTF-8 text or encoded source value.
- Fieldlet validates and converts it in the browser, then provides copy-ready output.
Last reviewed for accuracy:
Worked examples
How the result is produced
Text is converted to UTF-8 bytes before encoding. Standard Base64 uses plus, slash, and optional equals-sign padding; Base64URL substitutes hyphen and underscore and this interface omits padding when encoding. Decoding normalizes the selected alphabet before interpreting bytes as UTF-8.
- Base64 increases size by roughly one third
- Standard padding may appear as one or two equals signs
- Base64URL replaces characters that are awkward inside URLs
- Encoding hides neither meaning nor secrets from someone who can decode it
Choose the alphabet required by the destination
Standard Base64 is common in files, MIME content, and data encodings. Base64URL is designed for URL and filename contexts by replacing plus and slash; protocols such as token formats can also prescribe whether padding is present.
- Use standard mode unless the format specifies Base64URL.
- Do not assume the two alphabets are interchangeable without normalization.
- Never treat encoded secrets as encrypted data.
References
These primary references document standards or definitions used in the explanation above.
Limitations and common mistakes
- This text-focused interface is not a general large-file encoder.
- A system may require padded or unpadded Base64URL, so follow the destination protocol's exact convention.
Common questions
Is Base64 encryption?
No. Base64 is an encoding format and provides no confidentiality or security by itself.
Can Base64 encode Unicode text?
Yes. Fieldlet converts the text to UTF-8 bytes before Base64 encoding and reverses that process when decoding valid UTF-8 content.