Mortgage Amortization Calculator
Print| Total Principal Repaid | $0.00 |
| Total Cumulative Interest Paid | $0.00 |
Understanding how a home loan amortizes over time is essential for tracking your home equity buildup and managing long-term housing costs. **Mortgage Amortization** refers to the mathematical process of spreading out a loan into a series of equal monthly payments over a fixed term (such as 15 or 30 years). During the early years of a mortgage, the vast majority of your monthly payment is allocated toward interest charges, with only a small portion reducing your principal balance. Over time, this balance shifts until principal payments dominate. Our free Mortgage Amortization Calculator generates full monthly and annual loan amortization schedules, showing exact principal vs. interest payment breakdowns.
Whether you are evaluating a new home loan or tracking an existing mortgage schedule, read on for amortization formulas, annual payoff lookup tables, and step-by-step calculation guides.
How Mortgage Amortization Is Calculated
Amortization calculations use recursive interest math for each monthly payment period:
1. Monthly Interest Charge Formula:
The monthly interest owed is calculated on the remaining loan principal balance at the start of each month:
Monthly Interest Paid = Beginning Loan Balance × (Annual Interest Rate / 12)
2. Monthly Principal Paid Formula:
The principal portion is whatever remains of your fixed monthly Principal & Interest (P&I) payment after subtracting monthly interest:
Monthly Principal Paid = Standard Monthly P&I Payment - Monthly Interest Paid
3. Ending Balance Formula:
Ending Loan Balance = Beginning Loan Balance - Monthly Principal Paid
Annual Amortization Schedule Reference Table
The table below summarizes annual principal, interest, and remaining balance milestones for a $350,000 30-year fixed mortgage at a 6.50% interest rate ($2,212.24/month P&I):
| Loan Year | Total Annual Payments | Annual Principal Paid | Annual Interest Paid | Ending Principal Balance |
|---|---|---|---|---|
| Year 1 | $26,546.88 | $3,932.12 | $22,614.76 (85.2% Interest) | $346,067.88 |
| Year 5 | $26,546.88 | $5,108.75 | $21,438.13 (80.8% Interest) | $327,612.40 |
| Year 10 | $26,546.88 | $7,067.04 | $19,479.84 (73.4% Interest) | $297,145.20 |
| Year 20 (Tipping Point) | $26,546.88 | $13,514.88 | $13,032.00 (49.1% Interest) | $187,420.10 |
| Year 30 (Final Year) | $26,546.88 | $25,720.15 | $826.73 (3.1% Interest) | $0.00 (Fully Paid) |
Step-by-Step Calculation Example
A borrower takes out a $300,000 30-year fixed loan at 6.00% interest ($1,798.65/month P&I). Here is Month 1 vs. Month 2 amortization:
Step 1: Calculate Month 1 interest and principal split
Month 1 Interest = $300,000 × (0.06 / 12) = $1,500.00
Month 1 Principal = $1,798.65 (Payment) - $1,500.00 (Interest) = $298.65
Ending Month 1 Principal Balance = $300,000 - $298.65 = $299,701.35
Step 2: Calculate Month 2 interest and principal split on reduced balance ($299,701.35)
Month 2 Interest = $299,701.35 × 0.005 = $1,498.51
Month 2 Principal = $1,798.65 - $1,498.51 = $300.14
Ending Month 2 Principal Balance = $299,701.35 - $300.14 = $299,401.21
Result Summary:
In Month 1, only $298.65 goes to principal ($1,500 to interest). By Month 2, interest drops to $1,498.51, allowing $300.14 to reduce principal balance.
Frequently Asked Questions (FAQ)
What is a mortgage amortization schedule?
A mortgage amortization schedule is a complete table showing every periodic payment over the life of the loan, detailing the exact portion of each payment that goes toward interest versus principal, along with the remaining balance after each payment.
When does the “tipping point” occur in a 30-year mortgage amortization schedule?
On a standard 30-year fixed mortgage at 6.5% interest, the tipping point (where monthly principal payments exceed monthly interest charges) occurs around Year 19 to 20 of the loan term.
How does refinancing affect my mortgage amortization schedule?
Refinancing resets your mortgage amortization schedule back to Year 1 of the new loan term. While it may lower your monthly payment, it restarts the period of interest-heavy payments unless you choose a shorter loan term (such as a 15-year mortgage).
Can I change my amortization schedule by paying extra principal?
Yes. Making extra principal payments accelerates your amortization schedule, reducing total interest charges and causing principal payments to dominate much earlier in the loan life.