Generate a full loan payoff schedule and see the exact principal vs. interest split for every payment — with and without extra payments.
| Year | Principal | Interest | Total Paid | Balance |
|---|
Enter your loan amount, annual interest rate, and term. Add an optional extra monthly payment to see how much faster you can pay off the loan and how much interest you'll save. Set your start date to get accurate payoff month and year. Toggle the schedule between yearly summary and full monthly detail.
The chart shows your remaining balance over time. If you enter extra payments, you'll see two lines: one for the standard schedule and one showing your accelerated payoff. The gap between them represents interest savings.
With a fully amortizing loan, each payment is the same dollar amount but the split between principal and interest changes each month. The formula for the monthly payment is: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the principal, r is the monthly rate, and n is the number of payments.
In the early years, the vast majority of each payment is interest. On a 30-year $350,000 mortgage at 6.75%, about 87% of your first payment is interest. By year 25, more than half goes to principal. This is why extra payments in the early years have such a dramatic effect — they reduce the high-interest-accruing balance when it matters most.
Every extra dollar you pay goes directly to reducing your principal. This means less interest accrues next month, which means slightly more of your regular payment also goes to principal. The effect compounds over time. An extra $200/month on a $350,000 30-year loan at 6.75% saves approximately $75,000 in interest and cuts about 5.5 years off the loan.
The yearly view summarizes principal paid, interest paid, and ending balance for each calendar year — great for big-picture planning and tax purposes (mortgage interest is generally deductible). The monthly view shows every individual payment — useful for verifying your lender's statements or planning precisely when your balance will cross a threshold.