Amortization Calculator

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|Michael Chen, CFA, CFP®|Updated June 1, 2026Our Standards →

Last updated: June 21, 2026

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

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Amortization Calculator

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Calculate your loan amortization schedule with monthly breakdowns of principal and interest. See how extra payments save you money over time.

Loan Amount ($)

Annual Interest Rate (%)

Loan Term (years)

Extra Monthly Payment ($, optional)

Enter values above to see results.

Amortization Calculator — Complete Loan Guide

Understand exactly how every mortgage or loan payment splits between principal and interest — and see how extra payments can save you tens of thousands of dollars.

~75%

Of a 30-yr mortgage payment going to interest in year 1

$418K

Total interest on $300K at 7% for 30 years

5–7 yrs

Term reduced by bi-weekly payments on a 30-yr loan

1934

Year FHA created the self-amortizing mortgage

How Loan Amortization Works

Amortization is the process of paying off a debt over time through regular fixed payments. Each payment covers two parts: interest (the cost of borrowing) and principal (reduction of the loan balance). The split changes dramatically — early payments are mostly interest; later payments are mostly principal.

This happens because interest is calculated on the remaining balance. At the start, the balance is high, so the interest portion is large. As you pay down principal, the balance shrinks and each subsequent payment goes more toward principal. By year 25 of a 30-year mortgage, you may be paying 80%+ toward principal.

The fixed monthly payment is calculated using the annuity formula so that the loan reaches exactly $0 at the end of the term. Refinancing resets your amortization clock — you start over with a new schedule where most payments are again interest-heavy.

Key Amortization Facts

✔Year-1 payments: ~75% interest on a 30-yr loan

✔Extra principal payments reduce both balance and total interest

✔Bi-weekly payments create one extra monthly payment per year

✔Refinancing resets your amortization schedule

✔Points paid upfront reduce your rate and long-term interest

✔ARM loans reset amortization at each rate adjustment date

Amortization Formulas

Monthly payment (M)

M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1]
r = annual rate ÷ 12
n = total payments (years × 12)

P = principal. The fixed annuity formula. The payment is the same every month for the life of the loan.

Interest and principal split (month k)

Interest_k = Remaining_balance × r
Principal_k = M − Interest_k
Balance_k = Balance_{k-1} − Principal_k

High interest early (large balance) → shrinking interest as you pay down → accelerating equity build in later years.

Total interest paid

Total Interest = M × n − P
Interest % = (Total Interest / P) × 100

$300K at 7% / 30yr: M=$1,996 · Total paid=$718,560 · Interest=$418,560 (139% of the original loan). Rate and term dominate the outcome.

Extra payment savings

New balance = Balance − Extra_payment
New term = fewer months at same M
Interest saved = Original_interest − New_interest

Extra $200/mo on the above loan saves ~$92K and pays off 8 years early. Early extra payments are most valuable (balance is highest).

Common Amortizing Loan Types

Loan Type	Typical Term	Rate	Amortization	Best For
30-year fixed mortgage	30 yr	Fixed	Fully amortizing	Low monthly payment + long-term predictability
15-year fixed mortgage	15 yr	Fixed	Fully amortizing	Faster equity + 50% less total interest vs 30-yr
5/1 ARM mortgage	30 yr total	Fixed 5yr then adjusts	Fully amortizing	Buyers moving or refinancing within 5 years
Auto loan	3–7 yr	Fixed	Fully amortizing	Vehicle purchase; shorter term = less interest
Personal loan	1–7 yr	Fixed or variable	Fully amortizing	Debt consolidation, large purchases
Interest-only loan	5–10 yr IO then amortizing	Fixed or ARM	Deferred	Investors with short hold periods; high risk for others

History of Amortization

Pre-1930s

Before modern amortization, US mortgages were short-term balloon loans — 3–5 years, interest only, full principal due at maturity. When banks stopped renewing in 1929–1932, foreclosures hit 25% nationally, triggering the Great Depression housing collapse.

1934

The National Housing Act creates the FHA, which insures long-term self-amortizing mortgages of 20–30 years with equal monthly payments. This transforms US homeownership — no more balloon payment risk, making mortgages accessible to the middle class for the first time.

1938

Fannie Mae is chartered to buy FHA-insured mortgages from lenders, creating a secondary market. Banks originate loans, sell to Fannie Mae, and redeploy the capital. Mortgage liquidity is born, further expanding access to amortizing loans.

1970

Freddie Mac is chartered. Together with Fannie Mae, it standardizes amortization schedules nationally and introduces the first mortgage-backed security (MBS) in 1971, allowing investors to buy pools of amortizing loans.

2003–2008

The subprime boom introduces interest-only ARMs and negative-amortization "pick-a-pay" loans where borrowers could pay less than interest, causing balances to grow. When loans reset to fully amortizing payments, millions faced payment shock. The 2008 financial crisis results.

2010–present

Dodd-Frank Act creates the "Qualified Mortgage" (QM) rule prohibiting negative amortization and balloon payments. The CFPB requires lenders to provide a Loan Estimate with the full amortization schedule. Most US mortgages must now be fully amortizing.

Amortization Myths vs Facts

Myth

Making minimum payments is fine — you're still paying down your loan

Fact

On a $400K 7% 30-yr mortgage, after 2 years you've paid $63,900 but reduced your balance by only ~$8,000. The other $55,900 went to interest. Early extra principal payments have a disproportionately large effect because they reduce the base on which future interest is calculated.

Myth

Refinancing always saves you money if you get a lower rate

Fact

Refinancing resets your amortization clock. If you're 10 years into a 30-year mortgage and refinance into a new 30-year loan, you add 10 more years of interest. Always compare total interest paid over the remaining life, not just the monthly payment. Short remaining terms almost never benefit from refinancing.

Myth

The mortgage interest deduction saves most homeowners money

Fact

The 2017 Tax Cuts and Jobs Act raised the standard deduction ($27,700 for married couples in 2024). About 90% of filers now take the standard deduction and receive no marginal benefit from the mortgage interest deduction. Calculate your total itemized deductions before assuming tax savings.

Myth

Bi-weekly payments cut your loan term in half

Fact

Bi-weekly payments (26 half-payments/yr = 13 monthly equivalents) typically shave 5–7 years off a 30-year mortgage, not 15. The savings are real and substantial, but "cuts term in half" is a common sales exaggeration. You can achieve the same benefit by simply making one extra principal payment per year.

Frequently Asked Questions

What is an amortization schedule and why does it matter?▾

An amortization schedule is a complete table showing every payment over the life of a loan — date, total payment, interest portion, principal portion, and remaining balance. It shows exactly how much of each payment goes to the lender as profit (interest) versus building your equity (principal), letting you plan extra payments strategically.

How much interest will I pay on a $300,000 mortgage?▾

At 7% for 30 years: $418,560 in total interest (monthly payment $1,996). At 6%: $347,515 interest. At 5%: $279,767 interest. Choosing a 15-year term at 6.5%: only $162,750 interest total. Rate and term are the two most powerful variables — a 1% rate change on $300K over 30 years affects total interest by roughly $70K.

What happens to my amortization if I make extra principal payments?▾

Extra principal payments reduce your remaining balance, so less interest accrues each subsequent month. This shortens your loan term without changing your required monthly payment. Example: extra $200/month on a $300K 7% 30-yr loan saves ~$92,000 in interest and pays off ~8 years early. The earlier you make extra payments, the larger the impact.

Should I choose a 15-year or 30-year mortgage?▾

A 15-year mortgage has ~45% higher monthly payments but roughly half the total interest. The 30-year gives flexibility to invest the payment difference. Historically S&P 500 returns (~10% annual) have outperformed mortgage interest savings (~7%), favoring 30-year + invest. But only if you actually invest the difference — if you won't, the 15-year forces wealth-building.

What is negative amortization?▾

Negative amortization occurs when your payment is less than the interest owed, so unpaid interest gets added to your balance — your balance grows instead of shrinks. This happened with "option ARM" mortgages before 2008. Dodd-Frank now prohibits negative amortization in Qualified Mortgages. If you have an older ARM, confirm your minimum payment covers full interest.

How does refinancing affect my amortization schedule?▾

Refinancing pays off your existing loan with a new one. A new 30-year loan restarts your amortization — you'll again pay mostly interest initially. Break-even: (closing costs) ÷ (monthly payment savings) = months to break even. If you plan to stay longer than the break-even period, refinancing saves money net of closing costs.

What is an interest-only mortgage?▾

An interest-only (IO) mortgage requires only interest payments for an initial period (5–10 years), then converts to fully amortizing over the remaining term. Monthly payments jump sharply at conversion. IO loans are risky for typical homeowners because you build zero equity during the IO period. They make sense primarily for short-term investors.

Can I pay off my mortgage early without a penalty?▾

Most modern US residential mortgages have no prepayment penalty, especially Qualified Mortgages under Dodd-Frank. However, some jumbo, commercial, and older loans may have prepayment penalties (typically a percentage of remaining balance, declining over 3–5 years). Always check your loan documents or ask your lender before making large extra payments.

What is a balloon mortgage?▾

A balloon mortgage has payments calculated on a 30-year schedule but the entire remaining balance is due in 5–7 years. It requires refinancing or selling at maturity. Common in commercial real estate and bridge financing. Balloon mortgages contributed to the 1930s foreclosure crisis; modern US QM rules prohibit them for most residential loans.

How do I find the mortgage interest deduction amount?▾

Your lender sends Form 1098 (Mortgage Interest Statement) by January 31 showing total mortgage interest paid in the prior year — this is the amount eligible for Schedule A itemized deduction. You can also read it from your amortization schedule by summing all interest values for the year. Remember: only useful if total itemized deductions exceed the standard deduction.

Does a shorter loan term always save more money?▾

In raw interest paid: yes, always. 15-year vs 30-year at comparable rates saves $200,000–$400,000 in interest on a $400K loan. But the extra monthly payment (∼$830/month on $400K) invested at 8% for 15 years grows to ~$285,000. Net advantage depends on investment returns vs mortgage rate spread and personal discipline.

How does the amortization of a car loan differ from a mortgage?▾

Car loans amortize the same way mathematically, but over much shorter terms (3–7 years). The shorter term means payments are more principal-heavy from the start. One key difference: cars depreciate, while homes typically appreciate. A car loan underwater (owing more than the car is worth) is common in early years of a 72–84 month loan term, which is a financial risk if you need to sell or the car is totaled.

References

Consumer Financial Protection Bureau — Understanding Your Loan Estimate, cfpb.gov
IRS Publication 936 — Home Mortgage Interest Deduction, irs.gov
Freddie Mac — Primary Mortgage Market Survey, freddiemac.com
National Housing Act of 1934 — US Congress
Fabozzi, F.J. (2016) — Fixed Income Mathematics, 5th Ed., McGraw-Hill
Dodd-Frank Wall Street Reform and Consumer Protection Act, 12 USC § 5301

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See Your Full Amortization Schedule

Enter your loan amount, rate, and term above to generate a complete month-by-month breakdown and discover how extra payments save you thousands.

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Reviewed by CalculatorApp.me Finance Team

Amortization Calculator — 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 — 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 × [r(1+r)^n] / [(1+r)^n − 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 × [0.005417(1.005417)^360]
    / [(1.005417)^360 − 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 × Monthly Rate
Principal portion = Payment − Interest portion
New Balance = Old Balance − Principal portion

Month 1 ($350K at 6.5%):
Interest = $350,000 × 0.005417 = $1,895.83
Principal = $2,212.24 − $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:
  • $103,821 in interest saved
  • 83 fewer payments (6.9 years earlier)
  • 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 × [(1+r)^n − (1+r)^k] / [(1+r)^n − 1]

Where k = payments already made

Example (balance after 5 years / 60 payments):
B(60) = $350,000 × [(1.005417)^360 − (1.005417)^60]
        / [(1.005417)^360 − 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 #	Payment	Principal	Interest	Balance
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 — 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 — 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 — 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

Federal Reserve

Mortgage Debt Outstanding

Total US mortgage debt reached $12.52 trillion in Q4 2023, accounting for 70% of all household debt. The average mortgage balance is approximately $244,000.

Consumer Financial Protection Bureau

Explore Interest Rates Tool

CFPB data shows the median 30-year fixed rate was 6.81% in Q4 2023. Even a 0.5% rate difference on $350K changes total interest by ~$40,000 over the loan term.

Freddie Mac — PMMS

Primary Mortgage Market Survey

Freddie Mac's weekly survey tracks mortgage rates since 1971. The all-time low was 2.65% (Jan 2021) and the 52-year average is approximately 7.74%.

National Association of Realtors

Home Affordability Index

NAR's affordability index fell to 91.7 in 2023 (below 100 = unaffordable for median family). Understanding amortization helps buyers evaluate true housing costs beyond the sticker price.

Amortization Myths vs. Facts

✕

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

✓

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) — and you save $194,000+ in total interest.

✕

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

✓

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.

✕

You should always choose the longest mortgage term for flexibility.

✓

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 — $194K more for the same house.

✕

Refinancing always saves money.

✓

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

Frequently Asked Questions

What does amortization mean?▼

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 — this pattern is called the amortization schedule.

Why do I pay so much interest at the beginning?▼

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 — this is the mathematical nature of amortized loans.

How do extra payments reduce my loan?▼

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 — even small extra amounts compound over time.

Should I choose a 15-year or 30-year mortgage?▼

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?▼

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?▼

Higher rates shift more of each payment to interest. At 4%, a $350K/30yr loan costs $251K total interest. At 7%, it costs $488K — nearly doubling the interest cost for just 3 percentage points higher.

Can I get an amortization schedule from my lender?▼

Yes — 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?▼

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?▼

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?▼

A fully amortizing loan has payments that cover all interest and principal by the end of the term — 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?▼

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?▼

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 — e.g., 6.5% rate in the 24% bracket → 4.94% effective rate.

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Amortization Calculator — Complete Loan Guide

How Loan Amortization Works

Key Amortization Facts

Amortization Formulas

Common Amortizing Loan Types

History of Amortization

Amortization Myths vs Facts

Frequently Asked Questions

References

Related Calculators

See Your Full Amortization Schedule

Amortization Calculator — Complete Guide

What Is Loan Amortization?

Amortization Formulas

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

History of Amortized Loans

FHA Introduces Amortized Mortgages

National Housing Act

30-Year Mortgage Becomes Standard

Truth in Lending Act (TILA)

Tax Reform Act — Mortgage Interest Deduction

Dodd-Frank and Qualified Mortgages

Key Research & Data

Mortgage Debt Outstanding

Explore Interest Rates Tool

Primary Mortgage Market Survey

Home Affordability Index

Amortization Myths vs. Facts

Frequently Asked Questions

References

Related Calculators

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