Inputs
APR is annual; payments monthly
Note: If APR is 0, payment becomes principal / months. Extra payment shortens the term.
Payment: —
Base monthly payment (excluding extra).
Total interest: —
Sum of interest across schedule.
Payoff time: —
Months to reach zero balance.
Amortization
—
| # | Date | Payment | Interest | Principal | Extra | Balance |
|---|
If you want: export CSV + yearly summary (principal/interest by year).