About Base64 Decoding
The reverse of the encoder: paste a Base64 string — or upload a .b64 file — and get the original text or binary data back. Everything happens locally in your browser, so the string you paste never leaves your machine.
You'll end up here when an API returns a Base64-encoded field and you
want to see what's actually inside, when a
data:image/png;base64,... URI needs to become a real
image file, or when someone hands you a JWT and you want to eyeball
its payload. Text, images, PDFs — if it can be Base64'd, this can undo
it.
Standard Base64 and the URL-safe Base64URL variant are both handled automatically, so there's no need to tell the tool which one you've got. If the decoded bytes turn out to be a file rather than text, hit "Download Decoded File" to save it as-is.
How to use the Base64 file decoder
Paste Base64 text or select a text file containing Base64 data, such as a .b64 file. For example, SGVsbG8= decodes to Hello. URL-safe Base64 is also accepted.
For encoded images, PDFs, or other binary data, choose Download Decoded File. The download uses the name decoded_file.bin; rename its extension only if you know the original file type.
This file decoder handles Base64-encoded content. It does not decrypt encrypted files or repair damaged documents. Binary data may not display as readable text even when decoding succeeds.
Frequently Asked Questions
What is Base64 decoding used for?
Base64 decoding converts Base64-encoded strings back into their original text or binary form. It is commonly used to decode data URIs, inspect tokens, recover email attachments and convert Base64 images back into files.
Can I decode a Base64 image and download it?
Yes. Paste a Base64 string or upload a .b64 file, then use the "Download Decoded File" button to save the decoded binary (for example a PNG or PDF) directly to your device.
Does the tool support URL-safe Base64URL?
Yes. The decoder automatically detects URL-safe Base64URL strings (which use "-" and "_" instead of "+" and "/") and restores any missing padding before decoding.
Why does my decoded output show as binary data?
If the decoded bytes are not valid UTF-8 text, the input is probably a binary file such as an image, audio or document. Use the "Download Decoded File" button to save it, or paste a Base64 string that encodes plain text.