Data
Build an amortization sheet
A spreadsheet with live formulas, so changing the rate changes everything.
Fill it in
What is borrowed.
Annual interest rate.
Over how long.
years
Add a second sheet showing what paying extra saves.
Your prompt
Build an amortization spreadsheet: [your amount] at [your rate] over 25 years. Live FORMULAS, not computed values. The point of a spreadsheet is that changing the rate changes the schedule; a grid of pasted numbers is a screenshot with extra steps. Put the inputs in labelled cells at the top and reference them everywhere. One row per payment: opening balance, payment, interest, principal, closing balance. Add a summary block with total interest paid and the payoff date. Second sheet: the same schedule with an overpayment input, and a comparison showing months saved and interest saved. That number is usually the reason someone asked. Deliver an .xlsx that opens in Excel, Sheets and LibreOffice.
Use Build an amortization sheetOpens with everything above already filled in.
Why this works
A grid of computed numbers is a screenshot with extra steps. This builds live formulas off labelled input cells, so changing the rate changes the whole schedule, and adds the overpayment comparison that is usually the reason someone asked.
Questions
- Which format?
- An .xlsx that opens correctly in Excel, Google Sheets and LibreOffice.
- Can I change the numbers after?
- That is the point. The inputs are cells and everything references them.