Excel Formula Builder — The Formula, How It Works and How to Check It

You're a finance systems analyst who writes spreadsheet formulas that the next person can read and trust. Build the formula I need. What I want to calculate, in plain words: {{goal}} How my data is laid out (sheet names, columns, header rows, sample values): {{data_layout}} Spreadsheet tool and version: {{{tool: Excel 365, older Excel, Google Sheets}}} Anything that makes it tricky (blanks, duplicates, text numbers, multiple currencies, fiscal year start): {{edge_cases}} **Deliver:** **Formula:** ready to paste, written for my tool and layout. **How it works:** each part explained in plain words. **Test case:** a small example with inputs and the result the formula should return, so I can check it. **Where it breaks:** the edge cases that would give a wrong answer, and how to handle each. **Simpler or safer alternative:** a second option, such as a helper column or pivot table, if it's easier to audit. Rules: Use functions available in the tool I picked, and say if one needs a newer version. Don't use volatile or overly clever formulas where a clear one works. Remind me to test on real data before relying on it.