Base64 Encoder & Decoder
Encode text to Base64 or decode Base64 back to text. Supports Unicode and UTF-8 characters including emoji.
How to use this tool
- Select Encode or Decode mode.
- Enter your text (to encode) or Base64 string (to decode) in the input area.
- Click Convert to see the result.
- Use Swap to reverse the operation and swap input/output.
This tool uses TextEncoder and TextDecoder for correct Unicode/UTF-8 handling, rather than relying on btoa()/atob() alone (which only support Latin-1 characters).
Base64 Technical Architecture and Radix-64 Mapping
Base64 is standardized in RFC 4648 to safely transport binary payloads across legacy communications channels designed solely for ASCII text:
| Index Range | Binary Range (6 bits) | Output Character Set |
|---|---|---|
| 0 – 25 | 000000 – 011001 |
Uppercase A – Z |
| 26 – 51 | 011010 – 110011 |
Lowercase a – z |
| 52 – 61 | 110100 – 111101 |
Digits 0 – 9 |
| 62 – 63 | 111110 – 111111 |
Symbols + and / (or - and _ in URL-safe Base64) |
Client-Side Privacy Guarantee
Developers frequently use Base64 tools to inspect tokens, authorization headers, or database exports. With BrightKit, no string data leaves your workstation, ensuring zero exposure of credentials.
Frequently asked questions
Base64 splits binary bytes into 6-bit chunks. Since 2^6 = 64, each 6-bit chunk maps directly to one of 64 printable characters: A-Z (26), a-z (26), 0-9 (10), plus '+' and '/'. Padding is applied with '=' characters when the byte stream is not divisible by 3.
Standard browser `btoa()` only accepts Latin1 (single-byte) characters and errors on emojis or non-English text. BrightKit encodes text into UTF-8 byte sequences first via `TextEncoder` and URI encoding before applying Base64, guaranteeing full international Unicode compatibility.
No. Base64 is strictly a data encoding scheme, not encryption or hashing. It contains no secret key and can be instantly decoded by anyone. Never use Base64 to protect confidential data without proper AES or RSA encryption.
Because Base64 converts every 3 bytes (24 bits) into 4 text characters (32 bits), the data payload expands by exactly 4/3 or approximately 33.3%, plus any optional padding characters.
Base64 is widely used for HTTP Basic Authentication headers (`Authorization: Basic ...`), inlining small images and SVGs into CSS as Data URIs, email MIME attachments, and JWT (JSON Web Token) payload structures.