Base64 Decode

Base64 packs three bytes into four text characters drawn from a 64-symbol alphabet. Decoding reverses that: every group of four characters rebuilds three original bytes, which are then read as UTF-8 text to give you back the source string.

They encode the same bytes but pick different symbols for the last two alphabet slots. Standard Base64 uses '+' and '/', while base64url swaps in '-' and '_' so the string is safe inside URLs and filenames, and it often drops the '=' padding.

Yes. The tool converts '-' back to '+' and '_' back to '/', then re-adds the '=' padding to reach a multiple of four before decoding, so you can paste a base64url token exactly as you found it.

If the string contains characters outside the Base64 alphabet, or its length cannot be re-padded to a multiple of four, a red error message appears and the output stays empty. Check for stray characters, missing pieces, or text that was never Base64 in the first place.

Yes. The decoded bytes are passed through a real UTF-8 decoder, so multi-byte sequences like é, ñ, or 🚀 reassemble correctly instead of turning into garbled symbols.

No. Leading and trailing whitespace is trimmed and any internal spaces, tabs, or line breaks are removed before decoding, so Base64 that was wrapped across several lines still decodes cleanly.

No. Base64 is an encoding, not encryption. Anyone can reverse it in seconds, exactly as this tool does, so never rely on it to hide passwords, keys, or other secrets.

This tool decodes to text and shows the result in a textarea, so it suits strings that represent UTF-8 text such as JSON, tokens, or messages. Binary payloads like images decode to raw bytes that will not render as readable characters.

Yes. Decoding happens entirely in your browser using built-in JavaScript, and nothing you paste is ever sent to a server, so sensitive tokens never leave your device.