During cost calculation, Loan Amortization solves the part I worry about most: mental math and temporary formulas are error-prone. By keeping equal payment visible in the workflow, there is less manual cleanup, and it works for shopping, budgeting, and finance estimates, so it belongs in my regular tool list.
Equal payment vs equal principal
- Equal payment: same monthly payment for the entire term, mostly interest at first, principal later. Smoother but more total interest
- Equal principal: same principal each month, interest based on remaining balance, decreasing payment. Higher initial payment but less total interest
- Equal payment: M = P × i × (1+i)^n / ((1+i)^n − 1)
- Equal principal: M = P/n + remaining × i
Tips
- Equal principal saves more if you plan early repayment
- Equal payment is better for steady budgets
- Export CSV for further analysis in Excel or Google Sheets
- Combine with separate runs for blended mortgage scenarios