Encode (text ??Base64)

UTF-8 safe.

URL-safe (uses -/_ and no padding)

Plain text

Base64

Decode (Base64 ??text)

Whitespace and URL-safe characters are accepted.

Base64

Decoded

File ??Data URI

Embed an image, font, or other small file directly into HTML/CSS.

Source file

?뱨

Click to choose a file, or drag & drop

Best for images and small assets (< 10 MB)

Data URI

What Is Base64?

Base64 encodes arbitrary binary or text data using 64 printable ASCII characters (A?밵, a?뱙, 0??, + and /). It increases size by ~33% (4 output chars per 3 input bytes) but produces output that survives email, JSON, URLs, and other text-only transports.

When to Use It

Inline images in HTML/CSS ??background:url(data:image/png;base64,?? avoids a separate HTTP request. Best for icons under ~5 KB.
JWT / OAuth tokens ??typically URL-safe Base64.
Email attachments ??MIME uses Base64 internally.
Storing binary in JSON ??when you can't use a binary format like CBOR or MessagePack.

Standard vs URL-safe Base64

Standard Base64 uses +, /, and trailing = padding. URL-safe Base64 (RFC 4648 짠5) substitutes - and _, and usually omits padding ??so the encoded value can sit in a URL or filename without further encoding. This tool accepts both during decoding.