Amortization Calculator
Calculate loan amortization schedule with detailed payment breakdown of principal and interest.
Loan Details
Amortization: Spreading loan payments over time with fixed monthly amounts that include both principal and interest.
Monthly Payment
$1,580.17
for 360 months
Payment Breakdown
Amortization Schedule (First 12 Months)
| # | Date | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | Mar 2026 | $226.00 | $1,354.17 | $249,774.00 |
| 2 | Mar 2026 | $227.23 | $1,352.94 | $249,546.77 |
| 3 | Apr 2026 | $228.46 | $1,351.71 | $249,318.31 |
| 4 | May 2026 | $229.70 | $1,350.47 | $249,088.61 |
| 5 | Jun 2026 | $230.94 | $1,349.23 | $248,857.67 |
| 6 | Jul 2026 | $232.19 | $1,347.98 | $248,625.48 |
| 7 | Aug 2026 | $233.45 | $1,346.72 | $248,392.04 |
| 8 | Sep 2026 | $234.71 | $1,345.46 | $248,157.32 |
| 9 | Oct 2026 | $235.98 | $1,344.19 | $247,921.34 |
| 10 | Nov 2026 | $237.26 | $1,342.91 | $247,684.07 |
| 11 | Dec 2026 | $238.55 | $1,341.62 | $247,445.53 |
| 12 | Jan 2027 | $239.84 | $1,340.33 | $247,205.69 |
What is Loan Amortization?
Amortization is the process of paying off a loan through regular, scheduled payments over a fixed period. Each payment covers both principal (the borrowed amount) and interest (the cost of borrowing), with the proportion changing over time.
Key characteristics of amortized loans:
- Fixed payment: Same amount due each period
- Early payments: Mostly interest, little principal
- Later payments: Mostly principal, little interest
- Full payoff: Loan reaches zero balance at end of term
- Schedule transparency: Know exactly when you'll be debt-free
Common amortized loan types:
- Mortgages (15 or 30 years typical)
- Auto loans (3-7 years typical)
- Personal loans (1-7 years typical)
- Student loans (10-25 years typical)
Amortization Formulas
Understanding the math behind amortization helps you make smarter borrowing decisions:
Amortization Calculation Formulas
Where:
- M= Monthly payment amount
- P= Principal (loan amount)
- r= Monthly interest rate (annual rate ÷ 12)
- n= Total number of payments
- Interest Payment= Current Balance × Monthly Rate
- Principal Payment= Monthly Payment - Interest Payment
How Amortization Changes Over Time
The front-loaded interest problem:
In the early years of a loan, most of your payment goes to interest, not principal. This is why building equity takes time.
Example: $300,000 mortgage at 6.5% for 30 years ($1,896/month):
- Payment #1: $1,625 interest, $271 principal
- Payment #60 (Year 5): $1,527 interest, $369 principal
- Payment #180 (Year 15): $1,232 interest, $664 principal
- Payment #300 (Year 25): $668 interest, $1,228 principal
- Payment #360 (Final): $10 interest, $1,886 principal
Total paid over 30 years:
- Principal: $300,000
- Interest: $382,633
- Total: $682,633
You pay more in interest than the original loan amount over 30 years!
How to Use This Calculator
Our amortization calculator creates a complete payment schedule:
- Enter Loan Details:
- Loan amount (principal)
- Annual interest rate
- Loan term (years or months)
- Optional: Extra Payments:
- Additional monthly amount
- Annual lump sum payments
- One-time extra payment
- View Results:
- Monthly payment amount
- Total interest over loan life
- Complete amortization schedule
- Principal vs. interest breakdown by payment
Use the schedule to see how much you owe at any point and how extra payments affect total interest.
The Power of Extra Payments
Why extra payments are so powerful:
- 100% of extra payment goes to principal
- Reduces future interest calculations
- Accelerates equity building
- Shortens loan term significantly
Example: $300,000 mortgage at 6.5%, 30 years:
- Normal payments: 360 payments, $382,633 total interest
- $100 extra/month: 307 payments, $300,526 interest (save $82,107)
- $200 extra/month: 268 payments, $242,686 interest (save $139,947)
- $500 extra/month: 199 payments, $160,369 interest (save $222,264)
Strategies for extra payments:
- Round up to next $100 ($1,896 → $2,000)
- Bi-weekly payments (26 half-payments = 13 full payments/year)
- Apply windfalls (bonuses, tax refunds) to principal
- Apply payment increases when you refinance to lower rate
Amortization vs. Simple Interest
Amortized loans:
- Interest calculated on remaining balance
- Fixed payment covers varying interest/principal
- Common for mortgages, auto loans, personal loans
- Interest decreases as principal is paid
Simple interest loans:
- Interest calculated on original principal only
- Total interest known upfront
- Common for short-term loans, some auto loans
- Interest doesn't decrease with payments
Interest-only loans:
- Payments cover only interest for initial period
- Principal unchanged until amortization begins
- Lower initial payments, but no equity building
- Higher total cost over loan life
Refinancing and Amortization Reset
The refinancing trap:
When you refinance, amortization restarts. Even with a lower rate, extending the term can cost more in total interest.
Example: 5 years into a $300,000 mortgage at 7%:
- Current balance: ~$280,000
- Original total interest: $418,527
- Refinance to new 30-year at 6%: $324,086 more interest
- Refinance to 25-year at 6%: $247,661 more interest
- Refinance to 20-year at 6%: $182,116 more interest
Smart refinancing strategies:
- Match or shorten remaining term when possible
- Keep same payment amount even if minimum drops
- Calculate break-even point for closing costs
- Consider total interest over loan life, not just monthly payment
Worked Examples
Standard Mortgage Amortization
Problem:
Calculate the amortization for a $250,000 mortgage at 6% APR for 30 years.
Solution Steps:
- 1Principal (P): $250,000
- 2Monthly rate (r): 6% / 12 = 0.5% = 0.005
- 3Number of payments (n): 30 × 12 = 360
- 4M = $250,000 × [0.005(1.005)^360] / [(1.005)^360 - 1]
- 5M = $250,000 × [0.005 × 6.0226] / [6.0226 - 1]
- 6M = $250,000 × 0.0301 / 5.0226
- 7M = $1,498.88
- 8Total paid: $1,498.88 × 360 = $539,595
- 9Total interest: $539,595 - $250,000 = $289,595
Result:
Monthly payment: $1,498.88. Over 30 years, you'll pay $289,595 in interest—more than the original loan amount.
15-Year vs. 30-Year Comparison
Problem:
Compare a $200,000 mortgage at 6% for 15 years vs. 30 years.
Solution Steps:
- 130-year loan:
- 2 Monthly payment: $1,199
- 3 Total interest: $231,676
- 415-year loan:
- 5 Monthly payment: $1,688
- 6 Total interest: $103,788
- 7Difference:
- 8 Monthly: $489 more
- 9 Interest saved: $127,888
Result:
15-year costs $489 more monthly but saves $127,888 in interest. You own your home outright 15 years sooner.
Extra Payment Impact
Problem:
How much does $200 extra per month save on a $300,000 mortgage at 6.5% for 30 years?
Solution Steps:
- 1Standard payment: $1,896/month
- 2Standard total interest: $382,633
- 3Standard payoff: 360 months
- 4With $200 extra ($2,096/month):
- 5Extra payment goes 100% to principal
- 6New payoff: 268 months (22 years, 4 months)
- 7New total interest: $242,686
- 8Interest saved: $382,633 - $242,686 = $139,947
Result:
$200/month extra saves $139,947 in interest and pays off the loan 7 years, 8 months early.
Tips & Best Practices
- ✓Make one extra payment per year to pay off a 30-year mortgage in ~26 years
- ✓Bi-weekly payments equal 13 monthly payments per year instead of 12
- ✓Round up payments to the nearest $100 for easy extra principal
- ✓Apply tax refunds and bonuses directly to principal
- ✓Check that extra payments are applied to principal, not future payments
- ✓Consider a 15-year mortgage if you can afford 20% higher payments
- ✓When refinancing, keep the same payment amount to maintain payoff schedule
- ✓Review your amortization schedule annually to track progress
Frequently Asked Questions
Sources & References
Last updated: 2026-01-22