Amortization Calculator

Generate a full amortization schedule showing principal, interest, and balance for each payment period with extra payment support.

Reviewed by CalculatorApp.me Finance Team

Amortization Calculator β€” Complete Guide

Loan schedules, payment breakdowns, extra payment strategies, and mortgage amortization explained.

$1,768

Avg 30-yr payment ($350K/6.5%)

$286K

Total interest on $350K mortgage

63%

Interest portion of 1st payment

30 yrs

Standard amortization period

What Is Loan Amortization?

Amortization is the process of paying off a loan through regular, equal payments over time. Each payment is split between interest (charged on the remaining balance) and principal (reducing the balance). Early payments are heavily weighted toward interest, while later payments mostly reduce principal.

For a typical 30-year, $350,000 mortgage at 6.5%, the monthly payment is $2,212 (principal & interest only). In the first payment, $1,896 goes to interest and only $316 to principal. By the last payment, $2,198 goes to principal and just $14 to interest. Over the full term, you pay approximately $286,000 in total interest β€” almost the loan amount itself.

Our amortization calculator generates a complete payment schedule showing exactly how each payment is allocated, the balance after each payment, and the cumulative interest paid. You can model extra payments to see how prepaying principal dramatically reduces total interest and loan duration.

Amortization Formulas

Monthly Payment (Fixed Rate)
M = P Γ— [r(1+r)^n] / [(1+r)^n βˆ’ 1]

Where:
P = Loan principal
r = Monthly interest rate (annual/12)
n = Total number of payments

Example ($350,000 at 6.5%, 30 years):
r = 0.065/12 = 0.005417
n = 360
M = $350,000 Γ— [0.005417(1.005417)^360]
    / [(1.005417)^360 βˆ’ 1]
M = $2,212.24/month

This is the standard fixed-rate amortization formula used by all lenders.

Interest vs Principal Split
Interest portion = Balance Γ— Monthly Rate
Principal portion = Payment βˆ’ Interest portion
New Balance = Old Balance βˆ’ Principal portion

Month 1 ($350K at 6.5%):
Interest = $350,000 Γ— 0.005417 = $1,895.83
Principal = $2,212.24 βˆ’ $1,895.83 = $316.41
New Balance = $349,683.59

Early payments are ~86% interest. By month 180, the split is roughly 50/50.

Extra Payment Impact
Extra $200/month on $350K, 6.5%, 30yr:

Base: 360 payments, $446,007 total interest
With extra: 277 payments, $342,186 interest

Savings:
  β€’ $103,821 in interest saved
  β€’ 83 fewer payments (6.9 years earlier)
  β€’ Break-even: immediate

Yield equivalent: ~6.5% guaranteed, tax-free

Extra principal payments offer a guaranteed return equal to your interest rate.

Remaining Balance Formula
B(k) = P Γ— [(1+r)^n βˆ’ (1+r)^k] / [(1+r)^n βˆ’ 1]

Where k = payments already made

Example (balance after 5 years / 60 payments):
B(60) = $350,000 Γ— [(1.005417)^360 βˆ’ (1.005417)^60]
        / [(1.005417)^360 βˆ’ 1]
B(60) = $328,269

After 5 years, only $21,731 principal repaid
(from $132,735 total paid!)

After 5 years of a 30-year loan, you've repaid only ~6% of the principal.

Sample Amortization Schedule ($350,000 at 6.5%, 30yr)

Payment #PaymentPrincipalInterestBalance
1$2,212.24$316.41$1,895.83$349,683.59
12$2,212.24$337.28$1,874.96$346,086.52
60$2,212.24$438.17$1,774.07$327,064.51
120$2,212.24$605.47$1,606.77$296,061.59
180$2,212.24$836.47$1,375.77$253,574.67
240$2,212.24$1,155.50$1,056.74$193,685.92
300$2,212.24$1,596.27$615.97$112,000.75
360$2,212.24$2,198.33$13.91$0.00

Principal portion grows from $316/mo to $2,198/mo β€” interest decreases proportionally.

History of Amortized Loans

1930s

FHA Introduces Amortized Mortgages

Before the 1930s, most home loans were interest-only with balloon payments. The Federal Housing Administration (FHA) introduced fully amortizing, 15-year fixed-rate mortgages β€” revolutionizing homeownership.

1934

National Housing Act

The National Housing Act of 1934 created the FHA, establishing standards for mortgage lending including 20% down payments, fixed rates, and amortization schedules that banks nationwide adopted.

1948

30-Year Mortgage Becomes Standard

Post-WWII housing demand drove lenders to extend mortgage terms to 30 years, reducing monthly payments by ~25% compared to 15-year terms and making homes accessible to middle-class Americans.

1968

Truth in Lending Act (TILA)

Congress passed TILA requiring lenders to disclose APR, total interest costs, and amortization details. For the first time, borrowers could see the true cost of their loans.

1986

Tax Reform Act β€” Mortgage Interest Deduction

The Tax Reform Act preserved the mortgage interest deduction while eliminating deductions for other consumer interest. This made mortgages the most tax-advantaged consumer debt.

2010

Dodd-Frank and Qualified Mortgages

After the 2008 financial crisis, the Dodd-Frank Act established 'Qualified Mortgage' rules requiring fully amortizing payments, banning negative amortization, and capping debt-to-income ratios.

Key Research & Data

Amortization Myths vs. Facts

βœ•

A 15-year mortgage payment is double a 30-year payment.

βœ“

A 15-year payment is only ~40% higher than a 30-year. On $350K at 6.5%, payments are $3,049/mo (15yr) vs. $2,212/mo (30yr) β€” and you save $194,000+ in total interest.

βœ•

Making extra payments isn't worth it with low interest rates.

βœ“

Extra payments offer a guaranteed, tax-free return equal to your interest rate. Even at 4%, paying an extra $200/month on a $300K mortgage saves $44,000 and cuts 5 years off the term.

βœ•

You should always choose the longest mortgage term for flexibility.

βœ“

Longer terms cost dramatically more in interest. A 30-year $350K mortgage at 6.5% costs $446K in interest vs. $252K for a 15-year term β€” $194K more for the same house.

βœ•

Refinancing always saves money.

βœ“

Refinancing involves 2-5% closing costs ($7,000-$17,500 on $350K). You need to stay long enough for monthly savings to exceed costs β€” the 'break-even point' is typically 2-4 years.

Frequently Asked Questions

What does amortization mean?β–Ό
Amortization is paying a loan off gradually through equal periodic payments. Each payment covers accrued interest plus a portion of principal. Over time, the interest portion shrinks and the principal portion grows β€” this pattern is called the amortization schedule.
Why do I pay so much interest at the beginning?β–Ό
Interest is calculated on the outstanding balance. When the balance is highest (early in the loan), interest charges are also highest. As you pay down principal, less of each payment goes to interest β€” this is the mathematical nature of amortized loans.
How do extra payments reduce my loan?β–Ό
Extra payments go directly toward reducing principal. A lower balance means less interest accrues, so more of each future payment also goes to principal. This 'virtuous cycle' accelerates payoff dramatically β€” even small extra amounts compound over time.
Should I choose a 15-year or 30-year mortgage?β–Ό
A 15-year mortgage offers significantly lower total interest and a faster payoff, but higher monthly payments. Choose 15-year if you can comfortably afford 40% higher payments. Otherwise, take a 30-year and make voluntary extra payments for flexibility.
What is negative amortization?β–Ό
Negative amortization occurs when payments don't cover the interest due. The unpaid interest is added to the principal, causing the loan balance to grow. This was common in pre-2008 option-ARM loans and is now banned for Qualified Mortgages.
How does my amortization schedule change with a different rate?β–Ό
Higher rates shift more of each payment to interest. At 4%, a $350K/30yr loan costs $251K total interest. At 7%, it costs $488K β€” nearly doubling the interest cost for just 3 percentage points higher.
Can I get an amortization schedule from my lender?β–Ό
Yes β€” lenders are required to provide an amortization schedule or the information to create one. Our calculator generates detailed schedules matching your exact loan terms.
What is the difference between amortization and depreciation?β–Ό
Amortization applies to intangible assets or loan repayment. Depreciation applies to physical assets (buildings, equipment) losing value over time. Both spread costs over a period, but amortization in the loan context means systematic debt repayment.
Does rounding my payment up help?β–Ό
Yes! Rounding up to the nearest $50 or $100 is a painless way to make extra payments. Rounding a $2,212 payment to $2,300 ($88 extra) saves $25,000+ in interest and eliminates 28 payments (2.3 years).
What is a fully amortizing loan vs interest-only?β–Ό
A fully amortizing loan has payments that cover all interest and principal by the end of the term β€” balance reaches $0. An interest-only loan requires only interest payments for a set period, with principal due later (as a lump sum or amortized payments).
How do adjustable-rate mortgages (ARMs) affect amortization?β–Ό
ARMs recalculate the payment when the rate adjusts (typically every 1-5 years). The remaining balance is re-amortized over the remaining term at the new rate. This can significantly increase or decrease your payment.
Is mortgage interest tax deductible?β–Ό
In the US, mortgage interest on up to $750,000 of acquisition debt is deductible if you itemize (Tax Cuts and Jobs Act of 2017). This effectively reduces your after-tax interest rate β€” e.g., 6.5% rate in the 24% bracket β†’ 4.94% effective rate.

References

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Methodology, sources & limitations

This calculator uses a published formula and the values entered in the calculator to generate the result.

Formula
PMT = P Γ— [r(1+r)^n] / [(1+r)^n - 1]
Jurisdiction & units
Intended for US, IN, EU, GB, AU, CA. Supports both units where applicable.
Assumptions & limitations
Results use the inputs you provide and published formulas or rate assumptions. They are estimates, not financial, tax, lending, or investment advice.
Review status
Formula and automated QA completed June 21, 2026; independent professional review is pending. Next scheduled review: September 21, 2026.

Validation sources

  • CFPB Amortization Guide
  • Fannie Mae

Amortization Calculator β€” Answer & Method

Generate a full loan amortization schedule showing principal and interest breakdown per payment.

Formula: Amortization Payment

PMT = P Γ— [r(1+r)^n] / [(1+r)^n - 1]

P = Loan Amount (USD)
r = Monthly Rate (%)

Example Calculation

$200K at 6.5% for 30 years: $1,264/month, $255,360 total interest.

Important limitation

This is an estimate based on your inputs, not financial, lending, tax, or investment advice.

Key Facts

  • In an amortization schedule, early payments are mostly interest while later payments are mostly principal.

Sources & Validation

CFPB Amortization GuideFannie Mae

Related Calculators

Deterministic: YesAI-Generated Numbers: NoVerified: 2026-02-12

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