Encode binary data as Base64 ASCII text or decode Base64 strings back to original content. Useful for embedding images in HTML/CSS, transmitting binary through text-only protocols, encoding authentication credentials.
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Browser local processing works best on Desktop for files over 100MB.
Base64 encoding converts binary data into ASCII text using 64 printable characters (A-Z, a-z, 0-9, +, /). Takes 3 bytes (24 bits), splits into four 6-bit groups, maps each to a character from the 64-character alphabet. Results in ~33% size increase but enables transmitting binary through text-only channels—email systems, JSON APIs, embedded data URIs. Common use cases: embedding small images directly in CSS (data:image/png;base64,...), HTTP Basic authentication (username:password encoded), JWT tokens. Decoder reverses the process: maps ASCII characters back to 6-bit values, concatenates, splits into original bytes. This tool handles UTF-8 text encoding before Base64 transformation, properly processing emoji and international characters.
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"In my coding class, some kids thought Base64 was a way to hide messages. It's not! It's just a way to pack data so it can travel through the web easily. Don't use it for your passwords!"
Azeem Mustafa
Privacy Architect
Choose 'Encode' to convert text to Base64, or 'Decode' to convert Base64 to text.
Type or paste your content into the input box.
The result will appear instantly in the output box.
Click the 'Copy' button to save the result to your clipboard.
Use the 'Clear' button to start over.
Turn regular text into Base64 format
Hello World!
SGVsbG8gV29ybGQh
Encode username:password for HTTP Basic auth
admin:mypassword123
YWRtaW46bXlwYXNzd29yZDEyMw==
Convert Base64 back to readable text
VGhhbmtzIGZvciBjaGVja2luZyB0aGlzIG91dCE=
Thanks for checking this out!
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Base64 takes binary data (bytes) and represents it using only 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). **The process**: 1. Take 3 bytes (24 bits) of data 2. Split into 4 groups of 6 bits each 3. Map each 6-bit group to one of 64 characters 4. Result: 3 bytes become 4 Base64 characters **Size impact**: Base64-encoded data is ~33% larger than the original. This is the trade-off for text compatibility.
For text with special characters: 1. **First**: Convert text to UTF-8 bytes (handles emoji, accents, etc.) 2. **Then**: Encode those bytes to Base64 Example: 'Café' → UTF-8: [67, 97, 102, 195, 169] → Base64: 'Q2Fmw6k=' Our tool does both steps automatically. Some tools skip UTF-8, causing issues with non-ASCII characters.
You might see = or == at the end of Base64 strings. here's why: Base64 processes data in 3-byte chunks. If the last chunk is incomplete: - 2 bytes left: Add one = - 1 byte left: Add two == - 0 bytes left (perfect fit): No padding The padding tells decoders where the data actually ends. don't remove it!
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Learn more about this tool and related topics in our blog.
Peek under the hood of Filemint. A deep dive into WebAssembly, Web Workers, and the cutting-edge tech powering our private browser tools.
Boost your website speed by baking images directly into your code. Learn when (and when not) to use Base64 encoding for web assets.
