Proton Sheets is a privacy-first, web-based spreadsheet tool built into Proton Drive’s encrypted cloud workspace that lets users create, edit, and collaborate on spreadsheets while keeping all data fully end-to-end encrypted so that only authorized collaborators can access the content, not even Proton can see it, defending sensitive information from surveillance, data harvesting, or AI training. You can start a new spreadsheet directly within Proton Drive, import files from CSV, XLS, or Excel formats, and organize your data across multiple tabs with standard spreadsheet features such as built-in formulas (e.g., SUM, IF), conditional formatting, sorting, and charts/graphs to visualize numbers and trends for budgets, tracking, or project planning, and you can work in real time with others who have access. Proton Sheets supports real-time collaboration with shared editing and access control, lets you manage who can view or edit your files, and keeps version history secure.