Most spreadsheets begin with a moment. A holiday budget. A wedding guest list. A shared grocery plan. A calorie tracker you meant to keep “for just a few weeks.” They’re created to answer a specific question or organize a short stretch of life, then we move on.
The spreadsheet does not.
What we treat as a temporary scratchpad becomes something closer to a permanent archive — and a liability. Private information remains stored and accessible long after its original purpose has faded, gifting your personal records to platforms and AI systems that are designed to squeeze data for profit.
Proton surveyed 1,000 adults across the US, UK, Germany, and France to find out how people use spreadsheets. We asked how often they use spreadsheets, what kinds of personal information they store, how they share files, whether they still have access to old spreadsheets, and what they believe spreadsheet providers can see or do with their data.
The findings reveal the deeply intimate information that people put into spreadsheets and people’s worries about how Big Tech might retain access to that data indefinitely.
Spreadsheets are frightening identity maps
For most of us, spreadsheets are where everyday life gets organized.
Across countries, 71–77% of people use spreadsheets for budgeting and personal finance. In the US, nearly half (47%) track subscription or login-related information. In Germany , spreadsheets have become the primary tools for managing household projects (49%).
Taken together, this data can be analyzed to build an increasingly detailed picture of a person’s habits, finances, routines, relationships, and priorities. What began as life admin is suddenly used to personalize products, target advertising, or train AI systems.
When spreadsheets become permanent archives
Worse still, our research shows spreadsheets often outlive the moments they were created for, and are frequently shared more widely than people realize. Links sent to ex-partners, former flatmates, or old travel groups continue to work long after the relationship or project has ended.
In the US, over two-thirds of respondents said they still have access to spreadsheets or shared documents they no longer need. And in France, nearly one in four people said they use “anyone with the link can view” when sharing spreadsheets, meaning access will persist even when you no longer remember who has the link.
Oversharing is not a series of isolated mistakes, but a pattern of everyday behavior. Spreadsheets are created quickly, and forgotten slowly. A short-term health log shouldn’t become permanent history.
- In the US, 67% of respondents said they still have access to spreadsheets or shared documents they no longer need.
- 24% of French respondents said they use “anyone with the link can view” when sharing spreadsheets.
The convenience of account blur
Even when links are shared with caution, spreadsheets can escape their original context. We create and open files wherever it feels easiest at the time: a personal budget on a work laptop, or a shopping list in your employer’s Google account.
When boundaries blur this way, spreadsheets are no longer clearly tied to a single account or context. Files move between devices and logins, and people lose track of what data is out there, and who (or what machine learning algorithms) can access it freely.
Big Tech and AI privacy concerns
People are not certain about what happens to their data behind the scenes, according to our research.
Across countries, respondents believe their spreadsheet data may be used for:
- Ad targeting or profiling (39–42%)
- Training AI systems (27–40%)
- Automated content scanning (25–38%)
These concerns exist because they’re real. On most Big Tech platforms, like Google and Microsoft, your spreadsheets are actively scanned. The same services that help you search, sort, and share files can also read what is inside them. Because the sheets are not end-to-end encrypted, these companies retain keys to unlock the contents and could even share them with third parties.
Information you once wrote down for yourself can continue to be analyzed long after you have stopped thinking about it. When personal spreadsheets live across multiple apps and accounts, it becomes harder to know who can see your data, how it is used, and just how long it will remain part of someone else’s systems.
What a better standard looks like
Spreadsheets are dense data sets and leave vast residue behind. A better standard means your spreadsheets should not quietly become long-term inputs for profiling, advertising, or AI systems. Personal data should always be under your control.
That is why we built Proton Sheets.
- End-to-end encryption: We cannot read your information or use it to train AI.
- User-controlled encryption keys: Only authorized collaborators can access content.
- Secure collaboration: Owners retain a clear view of who can view or edit a spreadsheet.
- Familiar tools: Enjoy the same collaborative, productive experience you’re used to with real-time editing, formats, and formulas.
With Proton Sheets, the data inside your spreadsheet is treated as your private asset. We store and sync it, but we cannot read it. Your budgets, plans, health logs, and shared lists stay visible only to the people you choose, not to the platform itself.
You still get real-time collaboration, familiar spreadsheet features, and easy sharing. What changes is who can’t see your data.
