Base64 encoder and decoder
Encode UTF-8 text or decode valid Base64 text.
Your inputs
Your results
Ready when you areYour results will appear here.
How it works
Convert UTF-8 text to standard or URL-safe Base64, or validate and decode Base64 into UTF-8. Canonical padding bits are checked.
Read the source reference ↗A few things to know
Not encryption or a binary-file viewer. Invalid UTF-8 is rejected. Whitespace is ignored on decode; URL-safe output omits padding. One million input characters maximum.
When to use this tool
Inspect an encoded text value without confusing encoding with secrecy. UTF-8 conversion handles non-ASCII characters before Base64 encoding.
- Inspect a text token.
- Encode a UTF-8 value.
- Compare standard and URL-safe output.
How to use base64 encoder and decoder
Prepare the inputs
Paste the original text and keep a copy of it.
Choose the settings
Choose the conversion settings; identifiers are preserved as text.
Review and export
Review the output and download it before using it elsewhere.
Try the supplied example
Inputs
text: Hello, world!; mode: Encode UTF-8 text; alphabet: Standard
Result
The default example encodes Hello, world! as SGVsbG8sIHdvcmxkIQ==.
What it means
Anyone with the output can decode the original text.
Common mistakes to avoid
Do not treat encoded secrets as protected
Do not treat encoded secrets as protected.
Select the alphabet used by the original value
Select the alphabet used by the original value.
Frequently asked questions
Definitions, edge cases, and practical next steps for this tool. Search all tool FAQs ↗
Is Base64 encryption?
No. It has no secret key and is easily reversed.
Do emoji work?
Yes, text is converted to UTF-8 bytes first.
What is URL-safe Base64?
It substitutes - and _ for + and /; this tool omits padding in URL-safe output.
Can I decode an image file?
This mode is for UTF-8 text, not arbitrary binary bytes.
Is whitespace allowed while decoding?
Whitespace is ignored; other unexpected characters are rejected.
Why can a string fail canonical validation?
Invalid padding positions or nonzero unused padding bits do not represent canonical Base64.
Are my inputs uploaded or stored?
Processing happens locally in your browser. This tool does not upload inputs. Downloads stay on your device; sharing or opening them in another service is your choice.
What should I check before using the output?
Not encryption or a binary-file viewer. Invalid UTF-8 is rejected. Whitespace is ignored on decode; URL-safe output omits padding. One million input characters maximum.
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Sources and method
Use the references below to check definitions and platform guidance. The model’s scope and limits are explained above. Read our editorial standards.