Check a spreadsheet for personal data before you share it
Personal Data and Sharing Check is an add-on for Google Sheets™, published by AppGarden. It finds names, emails, NI numbers, bank details and health data — including on hidden tabs and in notes — and shows who can already see it. Nothing leaves Google.
Install free · See it in 60 seconds
Install: from the Google Workspace Marketplace™ listing, or in Google Sheets™ choose Extensions › Add-ons › Get add-ons and search for “Personal Data and Sharing Check”. Questions: support@appgarden.co.uk.
It reads only the one spreadsheet it is opened in, and no spreadsheet content ever leaves Google. How it uses your data is set out in full in the privacy notice. It helps with data minimisation and sharing hygiene; it is not legal advice.
See it in 60 seconds
A staff sheet → Check → a hidden Payroll tab found → Before I share with the accountant → Make share-safe copy → the copy re-scans clean → share the copy. (Video lands with the launch build; the demo spreadsheet below does the same job today.)
Try it: open the demo spreadsheet, choose Extensions › Personal Data and Sharing Check › Open check and press Check. Checking is free and unlimited.
Four things people don’t know
- Hidden tabs aren’t private. Anyone you share with can make a copy or download the file and see every tab. Why, and what to do.
- Deleting a column doesn’t remove it. Every editor can still see it in version history. Share a clean copy instead.
- Protected ranges can still be read. Protection stops editing, not viewing. What protection actually does.
- IMPORTRANGE shows other files’ data to everyone. The values travel with this file. Imported data and privacy.
What it finds
Personal data
- Names, emails, phones, addresses
- Dates of birth, NI and NHS numbers
- Bank details and card numbers
- Health and special-category hints
- Pay, secrets, pupil data
Hiding places
- Hidden tabs, rows and columns
- Cell notes and disguised text
- Imported data and dropdown lists
- Protected ranges, filters, charts
- Version history warnings
Sharing
- People outside your organisation
- Personal Gmail™ accounts on the file
- Questions about link sharing and web publishing
- Download, copy and expiry settings
- Before-I-share verdicts per audience
Every finding carries a rule code (PD-01, HD-03, SH-04…), so a report you read again in six months still says which check produced which line. See the guide for what each one means.
Who it’s for
HR and payroll, school business managers and data protection leads, charities and clubs, small businesses, accountants receiving client files, and anyone answering a subject access request from a spreadsheet.
Free and Pro
Free
£0
- Unlimited checks, hidden tabs and notes included
- Every finding, with masked samples and click-to-cell
- Before I share, with badge and checklist
- By-hand fix steps for everything
Pro
£39 per year, or £4.50 a month
- Everything in Free
- Share-safe copy and redacted download
- Find a person: cells, export, erase
- Data map tab, custom patterns, saved ignores
- 3 activations (Google accounts)
Your data
Your spreadsheet content never leaves Google. Detection runs in the sidebar, in your browser. The only network traffic this add-on makes is to the licence server, and only a licence key and an anonymous install id ever cross it. It asks for “this spreadsheet only” — never your whole Drive. Privacy notice · Security.
FAQ
Does it send my data anywhere? No. Detection, masking and the person search all run in your browser. Only a licence key and an anonymous install id ever leave it.
Does it change my sheet? Only when you choose Redact in place — and the default is a share-safe copy, which leaves the original untouched.
Is it GDPR compliance? No. It helps with data minimisation and sharing hygiene; it is not legal advice, and it does not decide lawful basis. The guide links to the ICO’s own pages.
Can it check all my Drive? No, by design. It checks the one spreadsheet it is opened in. That is the privacy promise.
What about comments? Comments can’t be read without full Drive access, which this add-on refuses on principle. The guide shows the 10-second manual check.
Which browsers and accounts? Desktop browsers (Chrome™, Edge, Firefox, Safari), Gmail™ and Workspace accounts. It does not run in the Google Sheets™ mobile apps. Some Workspace admins block add-ons — yours can allowlist it.
Is it affiliated with Google? No. It is published by AppGarden, an independent maker of Sheets add-ons.
Support
Email support@appgarden.co.uk. Send a screenshot of the card, never the file — a support mailbox full of customers’ staff sheets would contradict the product. Read the privacy notice first.
Articles
- Hidden tabs in Google Sheets™ aren't private: here's who can see them
- Does Google Sheets™ version history keep deleted data? How to share a clean copy
- How to check who a Google Sheet™ is shared with (and remove people)
- Find NI numbers, bank details and dates of birth in a Google Sheet™
- Answering a subject access request from a spreadsheet: a step-by-step guide
- Before you share a staff list: a 10-point checklist for Google Sheets™
- IMPORTRANGE and privacy: what people you share with can see
- School data in Google Sheets™: pupil lists, SEN and sharing
Google, Google Sheets™ and Google Workspace™ are trademarks of Google LLC. Personal Data and Sharing Check is not affiliated with or endorsed by Google.