Base64 Encoder / Decoder
Encode and decode Base64 strings.
Base64 Encoding in Plain English
Base64 is a way to represent binary data using only 64 printable ASCII characters: A–Z, a–z, 0–9, and two symbols (usually + and /). It's used whenever you need to embed binary content in a place that only supports text — for example inside a JSON payload, an email attachment, or a data URI in HTML.
How It Works
Base64 groups input bytes three at a time (24 bits) and re-slices them into four 6-bit chunks, each mapped to one of the 64 characters. If the input length isn't a multiple of three, the output is padded with= signs so its length is always a multiple of four. The output is about 33% larger than the input.
When Base64 Helps
- Embedding images inline with
data:image/png;base64,... - Encoding file uploads in JSON APIs where multipart isn't convenient.
- Carrying credentials in HTTP Basic Auth headers.
- Serializing binary blobs into text-only storage formats.
Base64 Is Not Encryption
Despite looking scrambled, Base64 is not encryption. Anyone can decode it instantly — including this tool. If you need to protect data, use real encryption (AES, for example) in addition to encoding.
URL-Safe Base64
Standard Base64 uses + and /, which have special meanings in URLs. A "URL-safe" variant replaces these with- and _. JWTs use this variant. If you need URL-safe output, run a search-and-replace after encoding.