%
Monthly payment
?
Total interest
?
Total repaid
?
Paid off
?
Payment schedule
What the schedule shows that a payment figure does not
- Where your money actually goes. On a 25-year loan at 5%, the first payment is mostly interest and barely touches the balance. The schedule makes that visible instead of leaving it as a surprise.
- The payment is rounded the way a lender rounds it. Up to the cent, not down. Rounding down leaves a few cents unpaid every month and pushes a 300-month loan into a 301st residual payment.
- The rows add up. The interest column sums to the interest total and the principal column sums to the amount borrowed, exactly — so the figures survive being checked in a spreadsheet.
- The final payment is the adjusted one. It is smaller than the others, because the balance rarely lands on a round number.
- Real dates, if you want them. Give a first payment date and every row is dated, so you can see which calendar month the loan ends in.
- Zero interest works. An interest-free instalment plan divides cleanly instead of dividing by zero.
The equivalent in Excel
The payment itself is =PMT(rate/12, months, -amount). Building the schedule around it means IPMT and PPMT per row, or a running balance you have to get right; the usual mistake is dividing the annual rate by 12 in one formula and forgetting it in the next.