# Hide personal data in a spreadsheet before you share it

> Drop a table. Each column that may hold personal data gets an action, and the preview shows the result.

Find names, emails, phone numbers, card numbers and IDs in a table, then remove, mask or swap them. Runs in your browser, and nothing is uploaded.

- Tool: [Anonymize spreadsheet](https://fixmint.cc/anonymize-spreadsheet)
- Category: [Spreadsheets & data](https://fixmint.cc/spreadsheets)
- Fixes: Names and emails in a table
- Runs in the browser: files and text stay on the device, no sign-up, free.

## How to hide personal data in a spreadsheet

1. Drop a CSV or Excel file and check the columns it flags as personal data.
2. Pick an action for each column: keep, remove, mask, pseudonym, hash or generalize.
3. Download the table. Download the key file only if you need to map pseudonyms back.

## Questions

### Is the output anonymous?

Not by itself. Pseudonyms replace names with tokens, and anyone with the key file, or who can match the other columns to other data, may still identify people. Treat the result as sensitive.

### How does it find personal columns?

It reads the header first (such as Email or Birth date), then the values: an email pattern, an IBAN that passes its check digits, a card number that passes the Luhn check. It is a guess, so check each column.

### Why does a hash need a salt?

The salt is random and made in your browser for this session. Keep it secret: someone who has the salt can test guessed phone numbers or IDs against your hashes.

### Is anything uploaded?

No. Detection, masking, pseudonyms and hashes all run in your browser.

## Related tools

- [CSV cleaner](https://fixmint.cc/csv-cleaner): Messy CSV with blanks and copies
- [Data type checker](https://fixmint.cc/data-type-checker): Column has mixed formats
- [CSV column profiler](https://fixmint.cc/csv-column-profiler): Need stats for every column
- [Find table relationships](https://fixmint.cc/find-table-relationships): How do these tables connect?