How to Read an Amortization Schedule
An amortization schedule shows exactly where every mortgage payment goes. Understanding it reveals why the early years cost so much in interest — and how to fight back.
What an Amortization Schedule Is
An amortization schedule is a table showing every single payment over the life of a loan: the payment number, the date, the total payment amount, how much goes to interest, how much goes to principal, and the remaining balance after each payment. For a 30-year mortgage, that's 360 rows of data.
Most homeowners never look at it. That's a mistake, because the schedule reveals something counterintuitive and important about how your loan actually works.
Why Early Payments Are Mostly Interest
Every monthly mortgage payment is split between interest and principal. The interest portion is calculated on your current outstanding balance. At the start of the loan, that balance is at its maximum — so the interest charge is at its maximum.
Consider a $300,000 mortgage at 7% over 30 years. Monthly payment: $1,996.
| Payment # | Total payment | Interest | Principal | Balance remaining |
|---|---|---|---|---|
| 1 | $1,996 | $1,750 | $246 | $299,754 |
| 12 | $1,996 | $1,732 | $264 | $296,850 |
| 60 (year 5) | $1,996 | $1,694 | $302 | $289,000 |
| 120 (year 10) | $1,996 | $1,617 | $379 | $276,000 |
| 180 (year 15) | $1,996 | $1,508 | $488 | $258,000 |
| 240 (year 20) | $1,996 | $1,351 | $645 | $231,000 |
| 300 (year 25) | $1,996 | $1,122 | $874 | $192,000 |
| 359 | $1,996 | $23 | $1,973 | $1,984 |
In payment 1, you send the bank $1,750 in interest and only reduce your loan balance by $246. After 5 years of payments (60 payments × $1,996 = $119,760 paid), your balance has only fallen from $300,000 to $289,000 — a reduction of $11,000 on $119,760 paid.
The Crossover Point
At some point in the loan, the principal portion of each payment finally exceeds the interest portion. For a 30-year mortgage, this crossover typically happens around year 20–22. Before that point, the bank is extracting more from each payment than you are.
For our $300,000 example, the crossover happens around payment 253 (just past year 21). After that, more than half of each payment reduces your balance. Before that: less than half.
What This Means for Extra Payments
Because extra principal payments reduce your outstanding balance immediately, they reduce the interest calculated on every subsequent payment. A one-time $5,000 extra payment in year 3 on our $300,000 example saves roughly $20,000–25,000 in total interest and shortens the loan by about 2.5 years. The math scales — extra payments made early in the loan have much larger effects than the same payments made late.
This is why the "pay a little extra early" strategy is so potent. You're not just paying $246 toward principal in payment 1 — you're paying $246 and eliminating all future interest charges that would have been applied to those 246 dollars over the remaining 359 payments.
How to Use Your Amortization Schedule
Pull up your schedule (your lender will provide one, or generate it with a calculator) and look at a few things:
- Year 5: How much have you actually reduced your balance? Most people are surprised by how little principal they've paid down.
- The crossover: Note when your principal payment first exceeds your interest payment. This is the milestone where each payment starts doing more for you than for the bank.
- Total interest: Scroll to the bottom. The total interest paid over the life of the loan is often shocking — typically 80–150% of the original loan amount at today's rates.
- Impact of extra payments: Use the calculator to model adding $100 or $200 per month and see the interest savings and time reduction.
Key points
- In early mortgage payments, the majority goes to interest, not principal — because interest is calculated on the large outstanding balance.
- The crossover point (when principal > interest per payment) typically occurs around year 20–22 of a 30-year mortgage.
- Extra principal payments made early have an outsized effect — they eliminate future interest on the prepaid amount.
- The total interest on a 30-year mortgage often equals or exceeds the original loan amount.
Frequently Asked Questions
Why do I pay so much interest at the start of a mortgage?
Because interest is calculated on the outstanding loan balance. At the start of the loan, the balance is at its maximum, so interest charges are highest. As you pay down the principal over time, the balance (and therefore the interest charge) decreases with each payment.
Can I get my amortization schedule from my lender?
Yes. Your lender is required to provide an amortization schedule at closing. You can also generate one using any mortgage calculator, or by entering your loan details into the amortization calculator above.
Does the schedule change if I make extra payments?
Yes. Extra principal payments shorten the loan and reduce total interest paid. Most amortization calculators allow you to model extra payments to see how they change the schedule.
What happens to the interest/principal split over time?
The ratio shifts gradually from mostly interest toward mostly principal. In early years, 80–90% of each payment goes to interest. By the final years, nearly 100% goes to principal.
Try it yourself