Base64 Decoder
Paste a Base64 string and decode it back to readable plain text instantly.
About the Base64 Decoder
The DevGizmo Base64 Decoder reverses the encoding process — paste any valid Base64 string and the tool immediately converts it back to human-readable text. It correctly handles multi-byte UTF-8 sequences, so decoded output preserves Unicode characters such as accented letters, CJK characters, and emojis. Decoding runs entirely in your browser; your data never leaves your device.
The tool validates the input before attempting to decode it. If the string contains characters outside the Base64 alphabet, or has incorrect padding, a clear error message is displayed and no corrupt output is shown.
How to Decode Base64
- Paste or type your Base64 string into the input field above.
- The decoded plain text appears automatically in the output field.
- Click the copy button to copy the result to your clipboard.
What Makes a Valid Base64 String?
A standard Base64 string uses only the characters A–Z, a–z, 0–9, +, and /. The length must be a multiple of four; if it is not, the string is padded with one or two = characters. Any string that does not meet these rules is invalid and cannot be decoded to a meaningful value. Common causes of invalid Base64 include truncated strings, URL-safe Base64 that uses - and _ instead of + and /, and strings with missing padding.