How the base64 encoder & decoder works
Base64 Encoder & Decoder converts standard binary and text data into ASCII characters using the Base64 radix-64 representation scheme defined in RFC 4648. Base64 is widely utilized in web development for embedding inline data URIs, encoding HTTP Basic Authentication credentials, transmitting binary attachments in MIME email, and handling webhook payloads.
Our implementation supports full UTF-8 Unicode text encoding (preventing common Latin-1 encoding errors) and processes everything in your browser without transmitting secrets across the web.
Step-by-step instructions
- Paste your plain text or Base64 string into the input area.
- Select Encode to generate Base64 or Decode to convert back to plain text.
- Copy your result with one click.
Radix-64 Binary-to-Text Mapping (RFC 4648)
3 bytes (24 bits) → 4 Base64 characters (6 bits each) using charset [A-Za-z0-9+/]Every 3 bytes of 8-bit binary input are split into four 6-bit integers, which are mapped to an index in the 64-character ASCII alphabet. If the input is not divisible by 3, '=' padding characters are appended.
Practical example
Plain text: 'FreeToolKit' → Base64 Encoded: 'RnJlZVRvb2xLaXQ='. Decoding 'RnJlZVRvb2xLaXQ=' restores 'FreeToolKit'.
Frequently asked questions
Is Base64 a form of encryption?
No. Base64 is an encoding format designed for data transmission compatibility, not encryption. Anyone can decode a Base64 string without a password.
Does this tool handle international UTF-8 characters?
Yes. Our encoder uses UTF-8 byte stream processing, properly supporting accented characters, Chinese, Japanese, Arabic, and emojis.
Are my API keys and tokens secure when pasted here?
Yes. Because the tool runs 100% client-side in your browser, no text is sent to our servers.