What this calculator helps you do
Generate a period-by-period table showing how each payment is divided between interest and principal. The calculation runs entirely in your browser; SENNA Finance does not receive the values entered into this tool.
Worked example
Using the default example—loan amount of $100,000, annual interest rate of 7.25%, number of months of 120 months, start month of January—the calculator returns monthly payment of $1,174.01; total interest: $40,881.25; total repayment: $140,881.25. Change the assumptions to match your own case rather than relying on the example.
Formula and calculation basis
Inputs are converted to the periodic units required by the formula. Results are calculated with full JavaScript numeric precision and rounded only for display.
How to interpret the result
Early payments usually contain more interest because the balance is higher. As the balance falls, more of the same payment goes toward principal.
Common mistakes to avoid
- Treating the scheduled balance as a payoff quote.
- Ignoring payment-date differences and daily-interest conventions.
- Assuming every lender rounds each period in the same way.
Limits and assumptions
This schedule uses monthly periods, a fixed rate, and mathematical rounding. Actual statements can differ because of dates, fees, payment timing, and lender rounding.
Outputs are estimates, not contractual quotations, regulated disclosures, tax advice, investment advice, or a substitute for professional review.
Frequently asked questions
Why does interest fall over time?
Interest is calculated on the remaining balance, so the interest portion generally declines as principal is repaid.
Is the final balance exactly zero?
The engine adjusts the last payment to avoid a small negative balance caused by rounding.
Can I export every row?
Yes. The CSV export includes the complete generated schedule.
Sources and reference context
External references provide educational context and do not imply endorsement of SENNA Finance.