Base64 Encoder / Decoder – Encode & Decode Online

Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It is used to safely transmit binary data over channels that only support text — such as embedding images in HTML, JSON payloads, or email attachments (MIME).

Standard Base64 uses + and / characters that have special meaning in URLs. URL-safe Base64 replaces + with - and / with _, and typically removes padding = characters. This makes the encoded string safe to use in URLs, query parameters, and filenames without percent-encoding.

No — Base64 expands data. Every 3 bytes of input produce 4 characters of output, increasing size by approximately 33%. It is an encoding scheme, not a compression scheme. For compression, use gzip or deflate before Base64 encoding.

Common uses include: embedding images inline in CSS or HTML (data: URIs), encoding binary file attachments in email (MIME), passing binary data in JSON APIs, storing binary blobs in databases that only support text, and encoding credentials in HTTP Basic Auth headers.