Amortization Schedule: How Payments Split Guide
Understand amortization schedules — how monthly payments split between principal and interest. Full guide with payoff acceleration and interest savings math.
Amortization Schedule — Direct Answer
An amortization schedule shows how each monthly payment splits between principal (loan balance) and interest (lender's fee). Early payments are mostly interest; later payments are mostly principal. On a $300,000 30-year mortgage at 6.5%, the first payment is 84% interest ($1,625) and only 16% principal ($311).
→ See your full schedule with our free amortization calculator
How Amortization Works
Each payment reduces the balance, but the split shifts over time.
Monthly Interest = Balance × (Rate ÷ 12)
Monthly Principal = Payment − Monthly Interest
New Balance = Balance − Monthly Principal
Where:
- Balance = remaining loan principal
- Rate = annual interest rate (decimal)
- Payment = fixed monthly payment
How to calculate the monthly payment
M = P × [r(1+r)^n] ÷ [(1+r)^n − 1]
Where:
- M = monthly payment
- P = principal ($300,000)
- r = monthly rate (annual rate ÷ 12)
- n = total number of payments (years × 12)
How to apply to a real loan
Example: $300,000 at 6.5% for 30 years
- r = 0.065 ÷ 12 = 0.005417
- n = 360
- M = 300,000 × [0.005417 × (1.005417)^360] ÷ [(1.005417)^360 − 1]
- M ≈ $1,896
How the split changes over time
| Year | Payment | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | $1,896 | $1,625 | $271 | $297,808 |
| 5 | $1,896 | $1,545 | $351 | $288,597 |
| 10 | $1,896 | $1,383 | $513 | $262,738 |
| 15 | $1,896 | $1,133 | $763 | $217,261 |
| 20 | $1,896 | $770 | $1,126 | $148,349 |
| 25 | $1,896 | $282 | $1,614 | $51,630 |
| 30 | $1,896 | $10 | $1,886 | $0 |
Amortization Schedule Example
Full 30-year loan breakdown
| Category | Amount |
|---|---|
| Loan amount | $300,000 |
| Interest rate | 6.5% |
| Term | 30 years |
| Monthly payment | $1,896 |
| Total paid | $682,633 |
| Total interest | $382,633 |
First 12 payments
| Month | Payment | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | $1,896 | $1,625 | $271 | $299,729 |
| 2 | $1,896 | $1,624 | $273 | $299,456 |
| 3 | $1,896 | $1,622 | $274 | $299,182 |
| 4 | $1,896 | $1,620 | $276 | $298,906 |
| 5 | $1,896 | $1,619 | $277 | $298,629 |
| 6 | $1,896 | $1,617 | $279 | $298,350 |
| 7 | $1,896 | $1,616 | $280 | $298,070 |
| 8 | $1,896 | $1,614 | $282 | $297,788 |
| 9 | $1,896 | $1,613 | $283 | $297,505 |
| 10 | $1,896 | $1,611 | $285 | $297,220 |
| 11 | $1,896 | $1,610 | $286 | $296,934 |
| 12 | $1,896 | $1,608 | $288 | $296,646 |
Early Payoff Strategies
Strategy 1: Extra monthly payments
Adding $100/month to a $300K 6.5% loan:
- Interest saved: ~$68,000
- Time saved: ~4 years
- New payoff: 26 years
Strategy 2: Bi-weekly payments
Pay half the monthly every 2 weeks = 26 half-payments = 13 full payments/year.
- Interest saved: ~$71,000
- Time saved: ~4.5 years
Strategy 3: One extra payment per year
Apply a 13th payment to principal annually:
- Interest saved: ~$76,000
- Time saved: ~5 years
Strategy 4: Refinance at lower rate
Refinance $280K at 5% instead of 6.5%:
- Monthly savings: ~$260
- Interest saved (over 30 yr): ~$93,000
Common Amortization Mistakes
Mistake 1: Only looking at monthly payment
A $50/month lower payment on a 30-year vs 15-year costs $100,000+ in extra interest. Fix: Compare total interest across terms, not just monthly.
Mistake 2: Making extra payments without specifying "principal"
Extra payments must be marked as "principal only" or the lender may credit them as next month's payment. Fix: Confirm "principal-only" with your servicer every time.
Mistake 3: Ignoring the amortization schedule before buying
Know your interest-to-principal ratio for the first years. Fix: Use an amortization calculator before signing.
Fixed vs Adjustable Rate Amortization
Fixed-rate
- Rate: Fixed for entire term
- Payment: Same every month
- Best for: Long-term ownership
Adjustable-rate (ARM)
- Rate: Fixed for initial period, then adjusts
- Payment: Can rise or fall
- Best for: Short-term ownership
Which amortization schedule do you get?
- Fixed: Same schedule for 30 years
- ARM: Two schedules — fixed period and adjusted period
Amortization Schedule FAQ
What is an amortization schedule?
A table showing each loan payment, its split between principal and interest, and the remaining balance.
How much of my mortgage goes to interest?
On a 30-year 6.5% loan, the first payment is 84% interest. By year 15, it's 60%. By year 25, it's 15%.
How can I pay off my loan faster?
- Add extra monthly payments
- Switch to bi-weekly payments
- Make one extra payment per year
- Refinance to a shorter term or lower rate
Does paying extra reduce interest?
Yes. Extra payments go directly to principal, reducing the balance that accrues interest. Every extra dollar saves 2–3 dollars in interest.
What's the difference between amortization and depreciation?
Amortization = paying down a loan (liability). Depreciation = spreading an asset's cost over time (asset).
Next Steps for Loan Analysis
- Mortgage Calculator — Full schedule
- Loan Calculator — Personal, auto, business
- Compound Interest Calculator — Growth
- Refinance Guide — Break-even math
- Simple vs Compound Interest — Interest types
Last updated October 2026. Verify lender-specific rules for extra payments.