Free Base64 Encoder and Decoder — Encode and Decode Base64 Online

Our free Base64 encoder and decoder converts text to Base64 and decodes Base64 strings back to plain text entirely in your browser. Supports standard and URL-safe Base64. All processing is client-side — your data never leaves your device. Essential for developers working with APIs, JWT tokens, email attachments and data URIs.

What is Base64?

Base64 is an encoding scheme that represents binary data as ASCII text using 64 printable characters. It is not encryption — it provides no security — but ensures binary data can be transmitted over text-based protocols like HTTP and email. The encoded output is approximately 33% larger than the original input.

Common Uses

• JWT tokens — header and payload sections are Base64URL encoded
• HTTP Basic Auth — username:password is Base64 encoded in the Authorization header
• Data URIs — embedding images directly in HTML/CSS
• API payloads — encoding binary data for JSON bodies
• Email attachments — MIME uses Base64 for non-text attachments

Base64 vs Base64URL

Standard Base64 uses + and / which are not URL-safe. Base64URL replaces + with - and / with _ and removes padding — making it safe for URLs, JWT tokens and cookies without percent-encoding.