⇄ Base64 Encoder / Decoder

// standard · URL-safe · live conversion

All encoding and decoding runs entirely in your browser. Your data never leaves your device.

Variant

Padding

Live

Plain text input

Input: 0 bytes

Base64 output

Output length: — Size ratio: —

Variant reference

Standard Base64 (RFC 4648 §4)

Characters Notes A–Z, a–z, 0–9, +, / = padding

Use for email (MIME), data URIs, binary-to-text encoding in most contexts where the output isn't placed in a URL.

URL-safe Base64 (RFC 4648 §5)

Characters Notes A–Z, a–z, 0–9, -, _ + → - / → _

Use in URLs, query strings, and JWT signatures. The + and / characters are replaced so the result is URL-safe without percent-encoding.

Encoding overhead: Base64 expands binary data by ~33% — every 3 bytes of input become 4 Base64 characters. Padding = characters align output to a 4-char boundary; stripping them is valid but the decoder must handle the missing padding.