What is Base64 Encoder & Decoder?
Base64 Encoder & Decoder is a web utility designed to encode plain text or binary data into Base64 format and decode Base64 strings back into original human-readable text. Base64 is a binary-to-text encoding scheme defined by RFC 4648 that represents 8-bit binary data using a set of 64 printable ASCII characters (A-Z, a-z, 0-9, +, /). Base64 encoding is used across web systems to transmit binary data—such as cryptographic signatures, API credentials, image data, and HTTP headers—over transport channels designed strictly for ASCII text.
How to use Base64 Encoder & Decoder
Select your operating mode: 'Encode' or 'Decode'. Paste your input text into the input area. The tool processes the input in real-time. Toggle UTF-8 encoding support to ensure international character sets, accented characters, and emojis encode cleanly without corruption. Copy the output or download it as a file.
Key features
- Bi-directional Base64 encoding and decoding
- Full UTF-8 Unicode character set support including international symbols and emojis
- RFC 4648 compliance with standard '=' padding handling
- URL-safe Base64 encoding toggle option (- and _ instead of + and /)
- Instant copy to clipboard and file export
- 100% private client-side browser execution
Common use cases
- Encoding Basic Authentication credentials (username:password) for HTTP Authorization headers
- Decoding payload tokens and encoded response bodies from web APIs
- Encoding binary data strings for safe inclusion inside JSON objects or XML fields
- Inspecting encoded query string parameters in web tracking URLs
Technical details & standards
The Base64 encoding algorithm converts groups of three 8-bit bytes (24 bits total) into four 6-bit index numbers, mapping each to its corresponding character in the Base64 alphabet. If the input data byte length is not divisible by 3, '=' padding characters are appended. All operations execute 100% client-side inside your browser JavaScript runtime, keeping passwords, keys, and private tokens strictly private on your machine.
Frequently asked questions
Is Base64 encoding a form of encryption?
No! Base64 is an encoding format designed for data serialization, NOT encryption. Anyone can decode Base64 strings back to original text instantly. Never rely on Base64 alone to protect sensitive data.
What is URL-safe Base64 encoding?
Standard Base64 uses + and / characters, which have special meanings in URLs. URL-safe Base64 replaces + with - and / with _ to make strings safe for URL query parameters.
Is my data safe?
All processing happens entirely in your browser. Your data never leaves your device and is never sent to or stored on a server.
Does it work offline?
Yes. Once the page has loaded, most tools keep working without an internet connection.