Payment $1,800—how much bought the house?
Month one on a typical fixed mortgage: most of your payment is interest because interest is charged on the whole balance you still owe. The schedule is not punishing you—it is showing arithmetic. The same payment later knocks bigger chunks off principal because the balance finally shrank.
Why you should look once with coffee, not panic at 2 a.m.
Amortization answers the only fair questions: How much of my life will this loan cost? Where does an extra payment bite first? If I refinance, do I reset the front-loaded interest profile? Skip the table and you are negotiating blind.
What amortization means in plain terms
A fixed payment loan repays in equal installments, but each installment splits into interest (cost of borrowing what you still owe) and principal (actually reducing debt). Early rows are interest-heavy because the owed balance is large.
How each row is built
- Start with beginning balance for the period.
- Interest piece ≈ balance × periodic rate (match day-count rules your loan uses).
- Principal piece = payment minus interest.
- Ending balance = beginning balance minus principal—repeat.
Early months: interest dominates (large balance) Later months: principal dominates (smaller balance) Total interest = sum of the interest column — long terms amplify this
Try it yourself
What feels unfair vs what is math
Feeling: “My payment should cut principal now.” Reality: interest = rate × balance — big balance, big interest slice Extra principal payments attack the balance directly — see the next rows change
Where schedules matter
- Mortgages
- Auto loans with level payments.
- Student loans—watch capitalization if payments do not cover accruing interest.
Sharp mistakes
- Calling amortization “interest front-loaded” as if it were moral—it is balance × rate.
- Comparing refinance savings using monthly payment alone without total interest over the years you will keep the loan.
- Ignoring escrow and insurance in household cash flow—they are not “interest,” but they are cash.
Use the calculator
FAQ
- Is amortization the same for ARMs?
Schedules reset when the rate resets; watch adjustment caps and new assumptions.
- Why does my first payment look almost all interest?
Because interest is computed on the full balance. As balance falls, more of each payment goes to principal.
- Does a lump-sum extra payment change the schedule?
Usually yes on the principal path—verify how your servicer applies prepayments.