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How to Read a Mortgage Amortization Schedule

By Jorge Sanchez · April 20, 2026 · 6 min read

Bottom line: In year 1 of a 30-year mortgage, roughly 87% of each payment goes to interest. By year 25, most of each payment is principal. That's amortization — and it's why extra payments early matter so much.

An amortization schedule is a complete table of every loan payment — showing exactly how much goes to interest, how much reduces your loan balance, and what you still owe after each payment. Understanding it is key to making smart decisions about your mortgage.

The Four Columns Explained

ColumnWhat It Shows
Payment #Which payment number (1–360 for a 30-year mortgage)
PrincipalAmount reducing your loan balance this month
InterestCost of borrowing this month — this is gone forever
Remaining BalanceWhat you still owe after this payment

Sample Amortization Table

From a $300,000 loan at 7% over 30 years (payment: $1,996/month):

PaymentPrincipalInterestBalance
1$246$1,750$299,754
12$260$1,736$297,085
60 (yr 5)$310$1,686$285,740
120 (yr 10)$374$1,622$267,879
180 (yr 15)$452$1,544$244,753
240 (yr 20)$546$1,450$213,822
300 (yr 25)$659$1,337$172,172
360 (yr 30)$1,984$12$0

Notice: in payment #1, only $246 of your $1,996 goes toward your loan balance. The other $1,750 is pure interest cost.

Why the Interest/Principal Split Shifts Over Time

Each month, interest is calculated on your remaining balance:

Monthly interest = Balance × (Annual Rate ÷ 12)
Month 1: $300,000 × (0.07 ÷ 12) = $1,750
Month 2: $299,754 × (0.07 ÷ 12) = $1,748.53

As your balance drops (slowly at first), each month's interest charge decreases, so more of your fixed payment goes to principal. This accelerates over time — which is why the last few years of a mortgage fly by.

How to Use the Amortization Schedule to Save Money

Mortgage Calculator with Amortization Schedule

Generate a full amortization table for your loan and see the impact of extra payments.

Generate My Amortization Schedule →

Jorge Sanchez · Live Event Production Specialist · CalQpro