Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Encode text to Base64 or decode a Base64 string back to plain text.
Base64 is a way of representing binary data (or any text) using only 64 safe, printable ASCII characters -- commonly used to embed data in places that only accept plain text, like email attachments, data URLs in CSS/HTML, or API payloads that need to transmit binary-ish content as a string. This tool converts text to Base64 and back, with correct UTF-8 handling so non-English text and emoji round-trip without corruption.
Choose Encode or Decode mode, type or paste your text, and the result appears instantly with a copy button.
Base64 encoding groups input bytes into sets of 3, then re-represents those 24 bits as four 6-bit values, each mapped to one of 64 characters (A-Z, a-z, 0-9, +, /). This is why Base64 output is always roughly 33% larger than the original data -- it trades some size for universal text-safety.
Developers embedding a small image or font as a data URL in CSS. Debugging an API payload or JWT token segment that's Base64-encoded. Encoding text for systems (like some email formats or config files) that only reliably handle plain ASCII.
Base64 is an encoding, not encryption -- it provides zero security or confidentiality, since anyone can decode it instantly. Never use Base64 alone to "hide" sensitive data; use real encryption if confidentiality matters.
Take the word "Man". Its three bytes in UTF-8 are 77, 97, and 110, which are 01001101 01100001 01101110 in binary. Joined into 24 bits and split into four groups of six, they become 010011, 010110, 000101, and 101110, or 19, 22, 5, and 46. Looking those up in the Base64 alphabet gives T, W, F, u, so "Man" becomes "TWFu". When the input is not a multiple of three bytes, the encoder pads the final group with one or two equals signs so the output length is always a multiple of four characters. That is why "Hello" (five bytes) ends with a single equals sign.
If decoding fails, check for the usual causes. Stray whitespace or line breaks may have been added when the string was copied from an email or terminal. The string may be truncated, missing its trailing equals signs, or copied with an extra character at either end. It may also be the URL-safe variant, which uses hyphens and underscores in place of plus and slash; this tool expects the standard alphabet, so replace those characters first. Finally, a string can be valid Base64 but decode to bytes that are not text, such as an image or compressed data, and in that case the output will look like garbage because the content was never meant to be read as characters.
Because every three bytes become four characters, encoded data is about a third larger than the original. Embedding a large image as Base64 in a page therefore increases the page size and prevents the browser from caching the image separately. It is usually best reserved for very small assets. For anything large, serve the file normally.
Anyone can decode a Base64 string in seconds, including with this tool. If a value is a password, API key, or personal data, encoding it does not protect it. Use proper encryption and secure storage, and never paste real secrets into any online tool if you are unsure where the data goes.
No -- Base64 is a reversible encoding scheme with no secret key, so anyone can decode it back to the original text instantly. It provides no security whatsoever.
The "=" is padding, added when the input's byte length isn't evenly divisible by 3, so the encoded output aligns to a full 4-character group.
Yes -- the encoder routes through proper UTF-8 byte encoding rather than a naive character-code approach, so multi-byte characters like emoji and accented letters decode back correctly instead of becoming garbled.
The Base64 may represent binary data such as an image or file rather than text, or it may have been encoded with a different character encoding. Only text encoded as UTF-8 will decode to readable characters here.
It is a variant that swaps plus and slash for hyphen and underscore so the string can sit safely in a URL. Convert those characters back before decoding with the standard alphabet.
This tool works with text input. Files are binary data and need a file-to-Base64 approach, so pasting file contents as text will not produce a correct result.
Line breaks, spaces, or a cut-off ending are common. Remove any extra whitespace and make sure the complete string was copied.
Reference: NIST Weights and Measures