What this decoder accepts
Paste a standard Base64 string containing UTF-8 text. Whitespace around or within the encoded string is ignored, making wrapped text easy to paste. Complete unpadded groups are accepted where the browser decoder permits them; malformed padding and non-alphabet symbols are rejected.
Encoded input and decoded output
SGVsbG8= → HelloY2Fmw6k= → café8J+Riw== → 👋SGVs bG8= → Hello because whitespace in the encoded input is ignored./w== decodes to a byte that is not valid UTF-8, so this text tool shows an error instead of replacing it with a misleading character.How to Use This Tool
- Paste only the standard Base64 value.
- Click Decode Base64.
- Review the decoded text, or use the error guidance to check the alphabet and expected file type.
- Copy Result copies the decoded text, including its whitespace.
Common Use Cases
Troubleshoot a failed decode
Copy only the encoded value: remove a data:…;base64, prefix, surrounding quotes, or a Basic authorization prefix. Base64url characters - and _ are not accepted here. Do not paste an entire dotted JWT as one Base64 string.
A valid Base64 value can represent an image, compressed file, or bytes in another character encoding. Those bytes may fail UTF-8 decoding; this does not prove that the original Base64 is corrupt. Use a binary-aware tool for files.
Verify what you received
Whitespace and line breaks in the decoded text are preserved. To check a round trip, copy the result into the encoder. Its output is padded standard Base64, so its spelling can differ from an unpadded input while representing the same bytes. Decoding takes place in your browser.