Base64 Encoder & Decoder

This tool converts text to Base64 and Base64 back to text. Pick Encode or Decode, paste your input, and the result appears alongside it with its size. You can copy it, download it as a text file, or swap the output back into the input to check the round trip.

It is built for text: any language and emoji, via UTF-8. Decoding validates the input first, so a mistyped character, broken padding or a truncated string is reported rather than turned into garbled output. This version doesn't encode or decode files such as images; if a Base64 string turns out to contain binary data, the tool says so.

1. Text becomes bytes. The text is converted to bytes using UTF-8. "Hello" is 5 bytes; an emoji is 4.
2. Bytes are grouped in threes. Each group of 3 bytes is 24 bits.
3. 24 bits become four 6-bit numbers. Each number (0–63) picks one character from the Base64 alphabet.
4. Padding fills the last group. If the data doesn't divide into threes, the output ends with one or two =.

That is why Hello encodes to SGVsbG8=: five bytes make one full group of three plus two leftover bytes, which need one padding character.

Base64 encodes bytes, so text first has to become bytes, and the usual choice is UTF-8. English letters take one byte each; accented letters, Hindi, Urdu and Arabic usually take two or three; Chinese and Japanese characters three; most emoji four. Decoding must use the same character encoding, or the text comes back garbled.

In JavaScript, the built-in btoa() only accepts characters that fit in a single byte, so calling it on "नमस्ते" or an emoji throws an error. This tool converts text with TextEncoder first and decodes with a strict TextDecoder, which is why Unicode round-trips exactly, and why Base64 that holds non-text bytes is reported instead of displayed as nonsense.

No. These three things are often confused, but they do different jobs:

• Encoding (Base64, URL encoding) changes how data is written so it can be transported. There is no key; anyone can reverse it.
• Encryption (AES, for example) scrambles data with a key so only someone with the key can read it.
• Compression (gzip, Brotli, ZIP) makes data smaller by removing redundancy.

Base64-encoded text looks unreadable, but it hides nothing: this page decodes it in a click. Don't rely on Base64 to protect passwords, tokens or personal data.

The tool accepts up to 2,000,000 characters of input, which covers everyday text comfortably while keeping your browser responsive. It is designed for text; it doesn't encode or decode files such as images or PDFs.

Your text is processed in your browser and is not uploaded to Q3 Labs. It isn't written to the URL or browser storage, and it is never sent to analytics. Decoded output is shown as plain text only: HTML or JavaScript inside it is never run or rendered. As with any web page, avoid pasting live secrets on a shared or untrusted computer.