Base64 Encoder / Decoder
Encode and decode text to and from Base64. Handles Unicode correctly.
Reference
What is Base64?
Base64 is a binary-to-text encoding scheme that represents binary data as printable ASCII characters using 64 symbols (A–Z, a–z, 0–9, +, /) plus = for padding. Every 3 input bytes become 4 output characters, expanding size by ~33%. Defined in RFC 4648.
Common uses
- Email attachments — MIME encodes binary attachments as Base64 so they can travel through text-only email protocols.
- Data URLs — Embed images/fonts directly in HTML/CSS as
data:image/png;base64,…without separate HTTP requests. - API payloads — Pass binary data (images, PDFs, keys) through JSON or query strings that only accept text characters.
Privacy
All encoding and decoding runs 100% in your browser. No data is ever sent to a server.