📅 Amortization Schedule Calculator
See how a fixed-rate loan pays down over time — the monthly payment, and a year-by-year breakdown of how much goes to principal versus interest.
The payment formula, then a 360-month loop
A fixed-rate loan uses the standard amortization payment formula, in which
P is the amount borrowed, i the monthly rate (the
annual rate divided by 12) and n the total number of payments:
Payment = P x i x (1 + i)^n / ((1 + i)^n - 1)For $300,000 at 6.5% over 30 years, i is 0.00541667 and n is 360, giving $1,896.20 a month. The calculator then walks all 360 months - interest is the current balance times i, the rest of the payment comes off the balance - and totals them into the calendar years shown.
Why the early years look so lopsided
Month one splits that $1,896.20 into $1,625.00 of interest and $271.20 of principal. Nothing is being held back: interest is charged on a balance that is still almost the whole loan.
| Year | Principal paid | Interest paid | Balance |
|---|---|---|---|
| 1 | $3,353 | $19,401 | $296,647 |
| 15 | $8,310 | $14,445 | $217,677 |
| 30 | $21,973 | $781 | $0 |
The balance does not fall below half the loan until month 257, in year 22. Total interest across the term is $382,633.
Frequently asked questions
What is the monthly payment on a $300,000 mortgage at 6.5%?
$1,896.20 over 30 years. Over 15 years the same loan costs $2,613.32 a month but only $170,398 in total interest instead of $382,633.
How much interest do I pay in the first year?
$19,401 of the $22,754 paid in year one is interest, leaving $3,353 off the balance. That is why selling after two or three years returns very little of what you have paid in.
How much does one extra payment a year save?
Adding $158 a month to this loan - one extra payment spread across the year - clears it in 24 years 2 months and cuts total interest to $295,377, a saving of $87,256.