All Tools VerseBase64 to CSV Decoder
Decode Base64 to CSV text - BOM stripped, delimiter auto-detected, URL-safe variant supported. Free, client-side, instant, offline, secure.
- Runs in your browser
- Nothing uploaded
- Free, no sign-up
Decode Base64-encoded CSV data back to spreadsheet-ready text. Auto-detects , / ; / tab / | delimiters, strips the UTF-8 BOM that Excel adds, and accepts URL-safe Base64 - all client-side.
How to Use Base64 to CSV Decoder
- Paste your Base64 string into the input field. It can be a single line or wrapped across many - the tool strips whitespace before decoding by default.
- Check the options. If the Base64 came from a URL or a JWT (uses
-and_), leave the URL-safe checkbox on. If your source already has correct=padding, auto-pad is a no-op. - Watch the stats line. As you type, you’ll see bytes decoded, estimated rows × cols, and the detected delimiter. If it says
delimiter: ;, you’ve got a European-style semicolon CSV. - Confirm BOM handling. If your Base64 was made from an Excel-saved CSV, the stats line will show
BOM stripped- Excel prepends a UTF-8 BOM and most downstream tools choke on it. - Check the row/col count. If the stats say
1 row × 1 col · probably not CSV, the payload isn’t really comma-separated data - maybe you meant the Base64-to-ASCII decoder instead. - Copy or download.
Copywrites the decoded text to clipboard;Download .csvsaves it asdecoded-<timestamp>.csvwith atext/csvMIME type so Excel picks it up cleanly. - Keyboard shortcut. Press
Ctrl+Enter(orCmd+Enteron Mac) to decode and copy in one step.
Frequently Asked Questions
What is Base64 to CSV conversion for?
It is commonly used to recover CSV data that was embedded in a JSON API response, email attachment, or data URI. Base64 encoding makes it safe to transmit CSV through text-only systems.
How does the tool detect the CSV delimiter?
After decoding Base64, the tool samples the first few rows and counts commas, semicolons, and tabs to identify the most likely delimiter. You can override this if auto-detection picks the wrong one.
What is a BOM and why is it stripped?
A Byte Order Mark is an invisible character some systems place at the start of UTF-8 files. It can break CSV parsers, so this tool removes it automatically after Base64 decoding.
Does this tool support URL-safe Base64?
Yes. Both standard Base64 (with + /) and URL-safe Base64 (with – _) are auto-detected. Missing padding is also handled automatically.
Is my CSV data secure?
Yes. All decoding runs in your browser. Your Base64 input and decoded CSV never leave your device, so sensitive data like customer lists or financial records stays private.
Do you log or save anything?
No. The tool is fully client-side. Nothing is logged, stored, or transmitted. When you close the tab the data is gone.
Is this tool free to use?
Yes, completely free with no sign-up and no limits on how many conversions you run.
What if the decoded content is not valid CSV?
The tool shows a preview of the decoded text so you can verify the content before assuming it is CSV. Invalid Base64 or non-CSV output triggers a clear error message.
Can I download the result as a .csv file?
Yes. After decoding, the tool offers a Download button that saves the result as a .csv file with proper encoding for opening in Excel or Google Sheets.
How large a Base64 string can I decode?
There is no strict limit. The tool has been tested with Base64 strings representing CSV files up to several megabytes, limited only by your browser memory.
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