Base64 Encoder & Decoder
Encode plain text to Base64 or decode Base64 strings back to text instantly — entirely in your browser using JavaScript's native btoa() and atob() APIs. Handles non-ASCII and Unicode characters correctly via UTF-8 pre-encoding.
How to Use the Base64 Encoder & Decoder
- 1
Select mode
Choose "Encode" to convert text to Base64, or "Decode" to convert a Base64 string back to plain text.
- 2
Enter your input
Paste or type your text or Base64 string into the input field.
- 3
Get your output
The result appears instantly in the output area.
- 4
Copy the result
Click Copy to copy the encoded or decoded output to your clipboard.
Key Features
Fully Private
Your text never leaves your browser — safe for API credentials, tokens, and private data.
UTF-8 Safe
Correctly handles all Unicode and non-ASCII characters via UTF-8 pre-encoding.
Instant
Encode or decode any string in milliseconds using native browser APIs.
Pro Tips
Use Base64URL mode (replacing + with - and / with _) when encoding values for use in URLs or JWT tokens.
HTTP Basic Auth headers use Base64 encoding of "username:password" — you can decode them here to inspect.
If decoding fails, check whether the input uses standard Base64 (with +/) or URL-safe Base64 (with -_).
Privacy Note
All processing in this tool runs entirely in your browser — no data is transmitted to any server. Your input is never logged, stored, or shared. This tool is free to use with no account or registration required.
Frequently Asked Questions
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Your input is processed locally in your browser and is never stored, transmitted, or shared with any server. See our Privacy Policy.