Spreadsheets remain the most widely used data analysis tool in the world because nearly every business process -- budgets, sales tracking, inventory, payroll, surveys -- ends up organized in rows and columns. Microsoft Excel is a desktop-installed (or Microsoft 365 cloud) application with the deepest set of advanced functions and is the standard in many corporate finance and accounting roles, while Google Sheets is free, browser-based, and built for real-time collaboration, making it popular with startups, NGOs, and remote teams. Both tools share the same underlying logic of cells, rows, columns, and formulas, so skills transfer almost completely between them, and most functions covered in this course work identically in both. Employers across finance, marketing, operations, and NGO program management routinely list spreadsheet proficiency as a required or preferred skill.