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Free online tool
Encode text or files to Base64 format, or decode Base64 back to its original form — instantly and securely in your browser.
Privacy: All processing happens locally in your browser. No text or files are uploaded or sent to any server.
No. All encoding and decoding processing happens entirely in your browser using local client-side JavaScript APIs. No files, text, or keys are ever sent to any remote server or stored anywhere.
Standard Base64 contains the characters '+' and '/' which have special meaning in URLs. URL-Safe Base64 (RFC 4648 Section 5) replaces '+' with '-' and '/' with '_'. It also typically removes the '=' padding characters, making the encoded text safe to pass in URL query parameters or HTTP requests without URL encoding.
Standard browser window.btoa only accepts binary/Latin-1 strings (0-255 range). Pasting Unicode characters like emojis, Chinese characters, or non-Latin alphabets usually throws a character range error. This tool converts input text into a UTF-8 byte array using TextEncoder before base64 encoding, ensuring Unicode strings encode and decode without corruption.
We limit files to 10 MB to ensure your browser remains fast and responsive. Large files require significant memory allocations during base64 conversion and can freeze or crash the browser page.
Yes! When you upload an image file in File Mode, the tool provides quick helper buttons to copy a pre-formatted HTML <img> tag or a CSS background-image style using the generated Base64 Data URI.