Encode text to Base64 or decode Base64 to text. Fast, free, runs in your browser.
Base64 is a binary-to-text encoding scheme that represents binary data as an ASCII string. It's commonly used to embed images in HTML/CSS, encode email attachments, transmit data in URLs, and store binary data in JSON.
Base64 encoding increases data size by approximately 33% — every 3 bytes of input become 4 bytes of Base64 output.
Common use cases: data:image/png;base64,... in HTML, JWT tokens, API authentication headers (Authorization: Basic base64(user:pass)), email MIME encoding.