Base64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to plain text instantly, fully in your browser.
Knowledge Base & Educational Companion: How Base64 Encoding Works
Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters. It is widely used to embed images in CSS/HTML, transmit data inside JSON, and encode email attachments.
1. The 64-Character Alphabet
Base64 maps every 3 bytes (24 bits) of input into 4 characters drawn from A–Z, a–z, 0–9, plus '+' and '/'. The '=' padding marks the final group when the input length is not divisible by 3.
2. URL-Safe Variant
Because '+' and '/' carry special meaning in URLs, the URL-safe variant substitutes them with '-' and '_' so the string can travel safely inside query parameters and filenames.
3. Encoding, Not Encryption
Base64 is encoding, not encryption — anyone can decode it. Use it for binary-safe transport and storage of text, never to protect secrets.