Base64 is a binary-to-text encoding scheme that represents binary data using a set of 64 printable ASCII characters (A-Z, a-z, 0-9, +, and /). It was designed to safely transmit binary content through text-only channels such as email (MIME), XML documents, and URL parameters. The encoding process takes every three bytes of input and converts them into four Base64 characters, which means the encoded output is roughly 33% larger than the original data. Despite this overhead, Base64 remains essential whenever binary data needs to be embedded in a text-based format.
During encoding, the input bytes are split into groups of six bits, and each group is mapped to one of the 64 characters in the Base64 alphabet. If the input length is not divisible by three, padding characters (=) are appended to the output. Decoding reverses this process, converting each Base64 character back into its six-bit value and reassembling the original bytes. This tool handles full UTF-8 text, so you can safely encode and decode strings containing international characters, emoji, and special symbols.
Base64 encoding is widely used for embedding images and fonts directly into CSS or HTML via data URIs, eliminating extra HTTP requests and improving page load performance. It is the standard encoding for email attachments in the MIME protocol, and it forms the basis of HTTP Basic Authentication where credentials are sent as a Base64-encoded username:password string. Developers also use Base64 to embed binary data in JSON payloads, store small files in databases as text fields, and encode cryptographic keys or certificates for transport. This browser-based tool processes everything locally, so your data remains private and never leaves your device.