Base64 Encoder & Decoder

Encode text to Base64 or decode Base64 back to readable text directly in your browser. All conversion executes locally in your browser memory with full UTF-8 Unicode support.

Interactive Base64 Encoder & Decoder Workspace

Switch between Encode (Text to Base64) and Decode (Base64 to Text) modes, validate UTF-8 characters and padding integrity, and copy or download results with instant in-browser execution.

✓ RFC 4648 Compliant ✓ Full UTF-8 & Unicode Support ✓ 100% Client-Side In-Browser Execution
Security Notice: Base64 is an encoding format, not encryption. Anyone who has Base64 data can normally decode it back to plaintext.

What Is Base64?

Base64 is a binary-to-text encoding algorithm defined by the Internet Engineering Task Force in RFC 4648. It converts arbitrary binary data or text into a printable ASCII string consisting of 64 distinct characters: A-Z, a-z, 0-9, +, and /. When the input byte count is not an exact multiple of 3, padding characters (=) are appended to complete the 4-character block.

Because legacy internet protocols like SMTP email and HTTP were historically designed to transmit 7-bit ASCII text, sending raw binary data across them frequently resulted in byte corruption. Base64 bridges this gap by mapping 3 8-bit bytes (24 bits) into 4 6-bit index characters, guaranteeing safe transmission across text-only communication channels with an overhead of roughly 33%.

How to Encode Text to Base64

  1. Select Encode mode: Choose 'Encode (Text to Base64)' in the conversion toolbar.
  2. Enter your text: Paste or type your plaintext into the editor. Unicode characters, emojis, and multiline text are supported without restriction.
  3. Run conversion: Click 'Encode to Base64'. The browser converts the UTF-8 bytes to standard RFC 4648 Base64 instantly.
  4. Copy or save: Copy the encoded Base64 string directly to your clipboard or download it as a text file.

How to Decode Base64

  1. Select Decode mode: Switch to the 'Decode (Base64 to Text)' tab.
  2. Paste your Base64 string: Paste the encoded payload into the input pane. Whitespace and line breaks are automatically handled.
  3. Run decoding: Click 'Decode to Text'. The tool verifies Base64 characters and padding, decodes the raw bytes, and reconstructs the UTF-8 string.
  4. Inspect output: Review the decoded plaintext in the output pane, then copy or export as needed.

Base64 Encoding Example

Consider the standard greeting text:

Hello World

When encoded into Base64, the 11-byte sequence is represented as:

SGVsbG8gV29ybGQ=

Decoding SGVsbG8gV29ybGQ= in reverse restores the exact original Hello World text.

Base64 Is Encoding, Not Encryption

Base64 is an encoding format, not encryption. Anyone who has Base64 data can normally decode it back to the original plaintext in milliseconds using any standard programming language, command-line utility, or online tool.

True encryption requires a secret key or password to reverse. Base64 uses a public, fixed conversion table with no cryptographic security whatsoever. Never use Base64 to protect sensitive passwords, tokens, API keys, or personally identifiable information.

UTF-8 and Unicode

Legacy JavaScript browser utilities such as btoa() and atob() only handle binary characters within the Latin-1 character range (code points 0 to 255). When passed emojis, accented characters, or non-Latin alphabets (like Japanese, Arabic, Bengali, or Cyrillic), they fail immediately with an InvalidCharacterError.

OwnFormatters implements the modern W3C TextEncoder and TextDecoder standards to convert text into raw UTF-8 byte arrays before Base64 serialization, guaranteeing seamless round-trip encoding and decoding for all international character sets.

Frequently Asked Questions

What characters are used in Base64?

Standard Base64 defined by RFC 4648 uses 64 characters: uppercase A-Z, lowercase a-z, digits 0-9, plus (+), and slash (/), along with equals (=) for padding.

Can Base64 data be safely transmitted in URLs?

Standard Base64 contains '+' and '/' which have special meanings in URL query strings. For URLs, the URL-safe variant substitutes '-' for '+' and '_' for '/', and often omits padding.

Why does Base64 increase data size?

Base64 maps every 3 bytes (24 bits) into 4 6-bit ASCII characters (32 bits), increasing total payload size by approximately 33%.

Is my text uploaded to a server?

No. Your text is processed locally in your browser and is not uploaded to OwnFormatters for Base64 conversion. No logs or records are ever kept.

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