Base64 Encoder

Convert plain text or binary data into Base64-encoded strings for safe transmission across text-based protocols.

Base64 Encoder

Convert plain text to Base64 encoding for safe transmission and storage.

Input Text

Base64 Output

About Base64 Encoding

Base64 encoding converts binary data into ASCII characters using a 64-character alphabet.

Common use cases:

API authentication (Basic Auth headers)
Data URIs for embedding images/files
Email attachments (MIME encoding)
Safe transmission of binary data over text protocols

What is Base64 Encoding?

Base64 encoding converts binary data into a string of ASCII characters using a 64-character alphabet (A–Z, a–z, 0–9, +, /). Because it represents arbitrary bytes using only printable characters, it is widely used to safely embed binary content in text-based formats such as JSON, XML, HTML, and email.

The output is approximately 33% larger than the input because every 3 bytes of input map to 4 Base64 characters. Padding characters (=) are appended when the input length is not a multiple of three.

Common Use Cases

Email Attachments (MIME): Binary files such as images or PDFs are Base64-encoded before being embedded in email messages. Data URIs: Images and fonts can be inlined directly in HTML or CSS as Base64 data URIs, eliminating extra HTTP requests. API Payloads: Credentials and binary blobs are Base64-encoded when passed in HTTP headers (e.g., Basic Authentication) or JSON request bodies. Cryptographic Tokens: JWTs and other signed tokens use Base64url (a URL-safe variant) to encode header and payload sections.

Tips

Base64 is an encoding scheme, not encryption — encoded data can be decoded by anyone without a key. Use the URL-safe variant (Base64url) when embedding encoded strings in URLs or filenames; it replaces + with - and / with _. Large inputs produce proportionally larger outputs; consider compression before encoding for bandwidth-sensitive scenarios.