Four things people don't know about Google Sheets™:

- Hidden tabs aren't private. Anyone you share with can make a copy or download the file and see every tab.
- Deleting a column doesn't remove it. Every editor can still see it in version history.
- Protected ranges can still be read. Protection stops editing, not viewing.
- IMPORTRANGE shows other files' data to everyone who can see this file.

Personal Data and Sharing Check answers one question before you share: what personal data is in here, where is it hiding, and who can already see it?

WHAT IT FINDS
- Personal data: names, emails, phone numbers, addresses, dates of birth, National Insurance and NHS numbers, bank and card details, and health or other special-category data.
- Hiding places: hidden tabs, hidden rows and columns, cell notes, white-on-white text, data far outside the visible area, IMPORTRANGE formulas and dropdown lists.
- Sharing: editors, viewers, external domains and personal Gmail™ accounts, plus questions about link sharing and web publishing.

BEFORE I SHARE
Tell it who the file is going to and it re-ranks everything for that audience: "Safe to share with sam@supplier.co.uk as Viewer" or "Not yet: 3 things to sort first", plus a checklist for the things no software can check.

WHAT PRO ADDS
Checking is free and unlimited. Pro (£4.50/month or £39/year, 50% off for education and charities) adds the doing: a share-safe copy with no version history, a redacted download, redact in place, Find a person (for subject access and erasure requests), the data map tab and custom patterns. 3 activations, 30-day full refund.

YOUR DATA
Detection runs in the sidebar, in your browser. Your spreadsheet's content is never sent anywhere — only a licence key and an anonymous install id leave it, and only when you activate Pro. It asks for "this spreadsheet only", never your whole Google Drive™.

This add-on helps with data minimisation and sharing hygiene. It is not legal advice and not GDPR compliance.

Google, Gmail™, Google Sheets™, Google Drive™ and Google Workspace™ are trademarks of Google LLC. Personal Data and Sharing Check is not affiliated with or endorsed by Google.