Mortgage Amortization Explained: Where Your Payment Goes
Ever wonder why you pay so much interest at the beginning of your mortgage and so little at the end? That’s amortization — and understanding it can save you thousands.
What Is Amortization?
Amortization is the process of paying off your mortgage through regular monthly payments. Each payment is split between interest and principal, but the ratio changes dramatically over time.
In the early years, most of your payment goes toward interest. As you pay down the balance, more goes toward principal.
A Real Example
On a $300,000 loan at 6.5% for 30 years (monthly P&I payment: $1,896):
Year 1
| Amount | % of Payment | |
|---|---|---|
| Interest | $19,358 | 85% |
| Principal | $3,398 | 15% |
Year 15
| Amount | % of Payment | |
|---|---|---|
| Interest | $13,092 | 58% |
| Principal | $9,664 | 42% |
Year 30
| Amount | % of Payment | |
|---|---|---|
| Interest | $872 | 4% |
| Principal | $21,884 | 96% |
In your first year, only $3,398 of your $22,756 in payments actually reduces your loan balance. The rest — $19,358 — is pure interest going to the bank.
Why This Matters
1. Extra Payments Have Massive Impact Early On
An extra $200/month toward principal in year 1 has a much bigger effect than the same extra payment in year 20. That’s because every dollar of extra principal in the early years eliminates interest on that dollar for the remaining 29 years.
$200/month extra on a $300,000 loan at 6.5%:
- Saves $95,413 in interest
- Pays off 7 years early
2. You Build Equity Slowly at First
After 5 years of payments on a $300,000 loan at 6.5%, you’ve paid $113,772 total but only reduced your balance by $21,277. Your remaining balance is still $278,723.
| Year | Total Paid | Principal Paid | Balance Remaining |
|---|---|---|---|
| 1 | $22,756 | $3,398 | $296,602 |
| 5 | $113,772 | $21,277 | $278,723 |
| 10 | $227,544 | $52,857 | $247,143 |
| 15 | $341,316 | $99,766 | $200,234 |
| 20 | $455,088 | $168,720 | $131,280 |
| 25 | $568,860 | $269,978 | $30,022 |
| 30 | $682,633 | $300,000 | $0 |
3. Selling Early Can Be Costly
If you sell after just 3 years, you’ve barely paid down your loan. Factor in 5-6% in selling costs (agent commissions, closing costs), and you could owe more than you net from the sale — especially if the market hasn’t appreciated.
How to Use Amortization to Your Advantage
Make One Extra Payment Per Year
Adding just one extra monthly payment per year (or switching to bi-weekly payments) can shave 5 years off a 30-year mortgage and save $60,000+ in interest.
See the bi-weekly savings with our calculator — it shows both monthly and bi-weekly payoff dates.
Round Up Your Payments
If your payment is $1,896, pay $2,000. That extra $104/month applied to principal saves $46,784 in interest and pays off your loan 4 years early.
Apply Windfalls to Principal
Tax refunds, bonuses, or other lump sums applied to principal early in your mortgage have an outsized impact.
A single $5,000 extra payment in year 1 of a $300,000 loan at 6.5% saves approximately $16,000 in interest over the remaining term.
15-Year vs. 30-Year Amortization
| 15-Year at 6.0% | 30-Year at 6.5% | |
|---|---|---|
| Monthly P&I | $2,532 | $1,896 |
| Total interest | $155,683 | $382,633 |
| Interest saved | $226,950 | — |
The 15-year loan costs more per month but saves $226,950 because the balance decreases faster and there are fewer years of interest.
View Your Amortization Schedule
Our PITI calculator generates a full month-by-month and year-by-year amortization schedule showing exactly how much interest and principal you pay each period, and your remaining balance over time.
Related
- Bi-Weekly vs Monthly Payments — save $60K+ by paying every two weeks
- 15-Year vs 30-Year Mortgage — see how term length changes amortization
- Mortgage Payment on a $300K House — see a real amortization schedule
- What Is PITI?