/ˈbeɪsˌsɪkstiˈfɔːr/
[from base (numeral system) + 64 (character set size)]
n.
A binary-to-text encoding scheme used to represent arbitrary binary data in an ASCII string format by translating it into a radix-64 representation. Base64 is commonly used in computing and data transmission systems where binary data must be safely transported over media designed to handle textual data.
Base64 works by dividing binary input into 24-bit groups, which are then split into four 6-bit values. Each 6-bit value is mapped to a printable ASCII character from a fixed set of 64 symbols, typically consisting of uppercase letters (A–Z), lowercase letters (a–z), digits (0–9), and two additional characters (usually + and /). Padding characters (=) may be appended to ensure the output length is a multiple of four characters.
The encoding is not a form of encryption and provides no confidentiality or security on its own. Instead, it is designed for data representation and transport, ensuring compatibility across systems that may not handle raw binary data correctly. As such, Base64 is frequently encountered in contexts such as email attachments (MIME), embedded images in HTML and CSS (data URIs), API payloads (JSON and XML), authentication headers (HTTP Basic Auth), and cryptographic material such as keys and signatures.
While Base64 increases the size of the encoded data by approximately 33%, it remains widely adopted due to its simplicity, reliability, and broad platform support. Variants of Base64 exist, including URL-safe Base64, which replaces certain characters to avoid conflicts in URLs and filenames.
In modern systems, Base64 is best understood as a transport encoding, bridging the gap between binary data and text-based protocols, rather than as a security mechanism.
Base64 Converter