Loan Amortization Calculator

Why do I pay more interest early in the loan?

Interest is calculated on your remaining balance each month. Since your balance is highest at the start, you pay maximum interest. As you pay down principal, the balance decreases and so does monthly interest accrual.

What happens if I make an extra payment?

The entire extra amount goes to principal, not interest. This immediately reduces your balance, which means future interest calculations are lower. Extra payments save substantial interest and accelerate payoff.

Is refinancing worth it if rates drop?

Refinancing is worth considering if: rates drop 0.5-1% or more, you plan to stay in the home 3+ more years, and closing costs are reasonable (typically 2-5% of loan amount). Use this calculator to compare scenarios.

Can I pay off my loan early without penalty?

Most mortgages don't have prepayment penalties, but check your loan documents. Some older mortgages or certain loan types do penalize early payoff. If no penalty exists, paying early saves substantial interest.

Should I get a 15-year or 30-year mortgage?

15-year mortgages have 40-50% higher monthly payments but save $150,000+ in interest. Choose based on: budget flexibility, ability to make the payment comfortably, and financial goals. Neither is objectively better.

What's the advantage of bi-weekly payments?

Paying bi-weekly (every 2 weeks) instead of monthly results in 26 payments yearly. Since monthly payments are 12 yearly, you make one extra payment annually. This can cut 4-7 years off a 30-year mortgage.

How do property taxes and insurance affect amortization?

Property taxes and insurance aren't part of the amortization schedule itself (principal and interest). However, your total monthly payment includes these if they're escrowed with your lender. This calculator shows only the loan portion.

What if my interest rate is variable/adjustable?

This calculator assumes fixed interest rates. For variable-rate loans (ARMs), the amortization changes when rates adjust. Use your current rate for planning, but understand that payments may increase when the rate resets.

How Amortization Schedules Work

An amortization schedule is a month-by-month breakdown of your loan repayment. Every single payment is divided into two parts: interest and principal. The remarkable (and often disappointing) truth: early payments are mostly interest.

On a $300,000 30-year mortgage at 6.5%, your first payment of $1,896 consists of $1,625 interest and just $271 principal. That means you own only 14.3% more of your home with your first payment. This front-loading is by design—the lender secures interest early, and you build equity slowly at first.

The Power of Compound Interest in Reverse

While compound interest works against you when you borrow, amortization schedules flip this: paying down principal accelerates equity building exponentially. Here's why:

• • Payment 1: Principal payment of $271 reduces balance by $271
• • Payment 2: Next month's interest is calculated on $299,729 (not $300,000), saving $1.76 in interest
• • This $1.76 reduction means payment 2 has slightly more principal than payment 1
• • By payment 180 (year 15), over half your payment goes to principal
• • By payment 360 (year 30), nearly all your payment is principal

This exponential acceleration is why the final years of a loan feel like rapid payoff—you're finally paying mostly principal.

Why Extra Payments Save So Much Interest

An extra $300 monthly payment on a $300,000 mortgage saves $163,000 in interest. This seems magical but is mathematically elegant:

• • That $300 extra immediately reduces your balance to $299,700
• • Next month, interest is calculated on $299,700, not $300,000 = $150 less interest accrued
• • That $150 monthly interest savings compounds across remaining loan life
• • You shave 8.5 years off a 30-year mortgage with this single change
• • Less time = exponentially less interest accrual

Amortization vs. Interest-Only Loans

Amortizing Loans (Standard): Payments include both principal and interest. Your balance decreases with each payment. You own more equity over time. Common: mortgages, auto loans, personal loans.

Interest-Only Loans: Payments cover only interest—no principal reduction. Balance stays the same throughout. At the end, you still owe the full original amount. Used in some investment scenarios, rarely for homes.

Amortizing loans are far superior for building wealth—you gradually own your asset, while interest-only means you never build equity.

The Mathematics of Loan Term Length

Longer terms lower payments but dramatically increase total interest. The difference is staggering:

• • 10-year loan: Payment ~$3,166, Total Interest ~$79,920
• • 15-year loan: Payment ~$2,897, Total Interest ~$221,358
• • 20-year loan: Payment ~$2,698, Total Interest ~$347,520
• • 30-year loan: Payment ~$1,896, Total Interest ~$382,512

Each 5-year increase lowers payment ~$250-400 but increases total interest $75,000-150,000. This shows why shorter terms, when affordable, save enormous money.

Refinancing and Amortization Reset

When you refinance, your amortization schedule starts over completely. This has important implications:

• • After 10 years of paying, you owe ~$245,000 on your $300,000 mortgage
• • If you refinance for another 30 years, you restart: mostly interest payments
• • You've potentially added years to your payoff timeline
• • Refinancing into a shorter term (10 years remaining → 10 years new) prevents this

Only refinance into equal or shorter terms unless lower rates offset the extended timeline.

How Interest Rates Impact Your Amortization

Higher interest rates dramatically change your amortization schedule. Comparing $300,000 mortgages:

• • 4.0% rate: Monthly $1,432, Total Interest $215,548
• • 6.5% rate: Monthly $1,896, Total Interest $382,512
• • 8.0% rate: Monthly $2,201, Total Interest $492,360

A 2% rate increase costs $166,964 more in interest on a $300,000 loan. This shows why even small rate differences matter significantly. Securing the lowest rate possible is critical.

Tax Deductions and Mortgage Interest

For homeowners, mortgage interest may be tax-deductible, which reduces the true cost of borrowing. Example:

• • Year 1 interest paid: $19,500
• • If you're in 22% tax bracket: Tax savings = $4,290
• • True cost of interest: $19,500 - $4,290 = $15,210

Note: Only applies if itemizing deductions (standard deduction is often larger). Consult your tax advisor for specifics.

Strategies to Pay Off Loans Faster

1. Bi-Weekly Payments: Pay half your monthly payment every 2 weeks. Results in 26 payments yearly (vs. 12 monthly), cutting 4-7 years off most mortgages.

2. Extra Principal Payments: Any extra toward principal compounds savings. Even $25 monthly makes a difference over 30 years.

3. Lump Sum Payments: Annual bonuses or tax refunds applied to principal create dramatic acceleration and interest savings.

4. Shorter Loan Terms: If you can afford it, choose 15-year over 30-year to save $150,000+ in interest despite higher payments.