Mortgage Amortization Calculator

This calculator builds your complete month-by-month payment schedule, shows exactly when principal finally overtakes interest in your payment, and lets you test how extra monthly or yearly payments change the payoff date and total interest.

For personal planning only — not financial advice.

Reviewed by CalculatorDrive Finance Editorial Board · Last updated

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Your Amortization Schedule

Enter your loan details to see a complete payment breakdown.

The short answer

On a $300,000 mortgage at 6.5% over 30 years, the payment is $1,896.20 a month, but principal doesn't overtake interest inside that payment until payment 233 — about 19.4 years in. Total interest over the full term is $382,633.47. Add $250 extra a month and the loan is paid off in 262 months instead of 360, saving $120,336.94 in interest.

Key takeaways

  • $300,000 at 6.5% over 30 years: $1,896.20/month, $382,633.47 total interest — more than the loan amount itself.
  • Principal doesn't exceed interest in the monthly payment until payment 233 (about year 19.4) — equity builds slowly for a long time.
  • $250/month extra pays the loan off 98 months (over 8 years) sooner and saves $120,336.94 in interest.
  • The schedule is a projection from your original terms — your real mortgage statement will differ slightly due to escrow, fees, or rate changes on an ARM.

The principal-interest crossover point

Every payment is the same $1,896.20, but the split inside it moves every month, since interest is charged on whatever balance remains:

Payment 1: mostly interest (balance is still $300,000)

Payment 233 (~year 19.4): principal finally exceeds interest

Payment 360: almost entirely principal (balance is nearly $0)

This is why home equity from paying down principal builds so slowly in the first half of a 30-year mortgage — for nearly two decades, more of every payment is servicing interest on the original balance than reducing it. Refinancing or moving a few years into the loan resets this curve, which is part of why frequent refinancing can quietly extend how long it takes to build equity.

What $250 extra a month does to the schedule

Standard +$250/month
Payoff time360 months262 months
Total interest$382,633.47$262,296.53

Because extra payments apply straight to principal, they shrink the balance that next month's interest is calculated on — a compounding benefit that adds up to more than the extra payments themselves. $250 a month for roughly 262 months (about $65,500 in extra payments) saves $120,336.94 in interest, nearly double what was paid in.

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Frequently Asked Questions

What is a mortgage amortization schedule?

An amortization schedule lists every monthly payment over the life of the loan, showing how much goes to principal versus interest and the remaining balance after each payment. On a $300,000 loan at 6.5% over 30 years, that means 360 payments of $1,896.20 each, but the principal-versus-interest split inside that payment changes every single month.

Why is so much interest paid early in a mortgage?

Interest is calculated on the remaining balance, which is highest at the start. On a $300,000, 6.5%, 30-year mortgage, principal does not overtake interest in the monthly payment until payment 233 — about 19.4 years in — which is why so little equity builds in the first decade and a half.

How do extra payments change the amortization schedule?

Extra payments reduce principal immediately, lowering every future interest charge. Adding $250 a month to the $300,000, 6.5%, 30-year mortgage above pays it off in 262 months instead of 360 — 98 months (over 8 years) earlier — and cuts total interest from $382,633.47 to $262,296.53, saving $120,336.94.

Is an amortization schedule the same as my mortgage statement?

A schedule is a projection based on your original terms. Your actual statement reflects real payments, escrow adjustments, rate changes on ARMs, and any fees. Use the schedule for planning, not as a legal payoff document.

What is the difference between amortization and term?

Amortization is the schedule over which the loan is repaid in full. On some loans — especially in Canada — the amortization period may be longer than the contractual term, meaning a balance remains due at renewal.

How do I use this mortgage amortization calculator?

Enter loan amount, annual interest rate, and loan term. Optionally add monthly or yearly extra payments, then click Calculate to view your full payment schedule with principal, interest, and remaining balance for each period.

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