An amortization schedule reveals the hidden story behind every loan — how much of each payment goes to interest versus principal, and how that ratio shifts dramatically over time. On a $300,000 30-year mortgage at 7%, your first payment of $1,996 puts only $246 toward principal while $1,750 goes to interest. By year 15, it splits roughly evenly. By year 25, nearly $1,600 goes to principal. Over the full 30 years, you pay $418,527 in total interest — more than the original loan amount. This calculator generates a complete payment-by-payment breakdown showing exactly where every dollar goes.
Amortization Calculator
Amortization Schedule
| Year | Principal | Interest | Balance |
|---|
Monthly Payment by Loan Amount and Rate
30-year fixed rate mortgage — principal and interest only
| Loan Amount | 6.0% | 6.5% | 7.0% | 7.5% | 8.0% |
|---|---|---|---|---|---|
| $150,000 | $899 | $948 | $998 | $1,049 | $1,101 |
| $200,000 | $1,199 | $1,264 | $1,331 | $1,399 | $1,468 |
| $250,000 | $1,499 | $1,580 | $1,663 | $1,748 | $1,834 |
| $300,000 | $1,799 | $1,896 | $1,996 | $2,098 | $2,201 |
| $350,000 | $2,098 | $2,212 | $2,329 | $2,447 | $2,568 |
| $400,000 | $2,398 | $2,528 | $2,661 | $2,797 | $2,935 |
| $500,000 | $2,998 | $3,160 | $3,327 | $3,496 | $3,669 |
| $750,000 | $4,496 | $4,741 | $4,990 | $5,244 | $5,503 |
How to Use This Calculator
- Enter your loan amount, interest rate, and term in years
- View your fixed monthly payment amount
- Examine the amortization schedule showing principal vs interest for each payment
- Note the crossover point — when your principal payment first exceeds the interest portion
- See the total interest paid over the life of the loan and how extra payments could reduce it
How It Works
An amortization schedule shows how each loan payment splits between principal and interest over the life of the loan. Early payments are mostly interest; later payments are mostly principal.
The basic rule:
- Monthly Payment = P × [r(1+r)^n] / [(1+r)^n - 1]
- P = loan amount, r = monthly interest rate, n = total number of payments
- Each month: Interest = Remaining Balance × Monthly Rate, Principal = Payment - Interest
- Extra payments go entirely toward principal, reducing total interest and loan term
Even small extra payments can save thousands in interest. An extra $100/month on a $280,000 mortgage at 7% saves over $60,000 in interest and pays off the loan 5+ years early.
Tips & Considerations
- Making one extra payment per year on a 30-year mortgage cuts the term by 4-5 years and saves tens of thousands in interest.
- In the first year of a 30-year mortgage at 7%, approximately 88% of your payments go to interest. This is why early payoff strategies have such a huge impact.
- Refinancing resets your amortization schedule. If you are 10 years into a 30-year loan and refinance to a new 30-year term, you restart the front-loaded interest cycle.
- Biweekly payments are the easiest hack — you make 26 half-payments per year instead of 12 full payments, adding one extra payment annually without noticing it.
Frequently Asked Questions
How is a mortgage payment calculated?
The monthly payment formula is M = P[r(1+r)^n]/[(1+r)^n-1], where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (years × 12). This gives you the fixed monthly principal and interest payment.
Why do I pay more interest at the beginning of a loan?
Interest is calculated on the remaining balance each month. At the start, your balance is highest, so most of your payment goes to interest. As you pay down principal, less interest accrues each month, and more of your payment goes to principal. This is how amortization works.
How much can I save with extra payments?
Extra payments can save significant money. For a $280,000 loan at 7% over 30 years, adding $200/month saves about $100,000 in interest and pays off the loan 8 years early. Even $50/month extra makes a meaningful difference over time.
Should I make extra payments or invest the money?
Compare your mortgage rate to expected investment returns. If your mortgage is at 7% and investments average 10%, investing may be better financially. However, paying off your mortgage provides guaranteed 'returns' equal to your interest rate and eliminates the payment obligation, reducing risk.
What is the difference between 15-year and 30-year mortgages?
A 15-year mortgage has higher monthly payments but much lower total interest. For a $280,000 loan at 7%, the 30-year payment is $1,863/month (total interest: $390,506). The 15-year payment is $2,517/month (total interest: $173,067) — saving over $217,000 in interest.
Does my monthly payment include taxes and insurance?
This calculator shows principal and interest only (P&I). Your actual monthly mortgage payment typically also includes property taxes and homeowner insurance (PITI), and possibly PMI if your down payment was less than 20%. These additional costs are held in an escrow account.