Base64 Decoder

Paste any Base64 string to decode it back to plain text. Handles standard and URL-safe Base64 automatically. Use the encoder to go the other way.

Runs in your browser · No data sent anywhere
Input — Base64 string
Output — decoded text
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Frequently Asked Questions

How do I know if a string is Base64?

Base64 strings contain only letters (A–Z, a–z), numbers, +, /, and = padding at the end. URL-safe Base64 uses - and _ instead of + and /. The string length is usually a multiple of 4 (when padded).

What does "Invalid Base64" mean?

It means the input contains characters not in the Base64 alphabet, or the padding is incorrect. Common causes: accidentally copying extra whitespace, truncated strings, or the data was encoded differently.

Can I decode a data URI?

Yes. Paste the full data URI (e.g. data:image/png;base64,iVBOR...) — the tool will strip the prefix and decode the Base64 portion automatically.

What if the decoded output looks like garbage?

The Base64 might encode binary data (an image, PDF, etc.) rather than text. Binary data can't be meaningfully displayed as text. You'd need to decode it to a file instead.