Loan calculator

Amortization Calculator

An amortization calculator shows how each loan payment is split between principal and interest over time. Build the full monthly schedule, a yearly summary, and model extra payments to see your early payoff date and the interest you would save.

Full monthly schedule Yearly summary Extra-payment payoff Principal vs interest Excel export
Build my schedule See the schedule

Educational estimate — principal & interest only, not a lender quote. Fees, escrow, and rounding can make a lender's schedule differ.

Amortization schedule

Build your loan amortization schedule

Enter the loan and (optionally) extra payments. Results and the full schedule update instantly — every payment split into principal and interest, with an early-payoff engine.

Works for any fixed-rate loan — mortgage, auto, personal, or student. This compares principal & interest only; lender fees, escrow, taxes, and insurance are not included.

Basic loan details$250,000 · 6.50% · 30 years

The core loan: how much you borrowed, the rate, and the term.

$

The amount borrowed (the starting balance).

%

Decimals supported, e.g. 6.5. Enter 0 for an interest-free loan.

In the unit selected on the right.

360 monthly payments total.

Used to label the payment dates.

Monthly payments (the standard for most loans).

Extra paymentsNone — optional

Optional. Add extra principal to pay the loan off sooner and cut total interest. Leave blank for a standard schedule.

$

Added to principal every month.

When the extra monthly amount begins.

$

A lump sum once a year, in the month below.

The yearly extra recurs in this month.

One-time extra payments

$
$
$

Each one-time amount is applied to principal in the chosen month (up to 10 rows). Rows with a zero amount are ignored.

Schedule settingsRounded to nearest unit

Display preferences for the schedule and result figures.

Affects how result figures are displayed; the underlying math is always to the cent.

Monthly payment

$1,580

First payment splits $1,354 interest / $226 principal. Payoff Jun 2056.

6-sheet workbook:SummaryMonthly scheduleYearly summaryExtra paymentsFormulasDisclaimer & sources
Built in your browser from your inputs · no upload

Total principal

$250,000

The amount borrowed.

Total interest

$318,862

Cost of borrowing over the loan.

Total paid

$568,862

Principal + interest.

Payoff date

Jun 2056

Last scheduled payment.

Final payment

$1,581

Trimmed to clear the exact balance.

Add extra payments above to see how much sooner you could be debt-free and how much interest you would save.

Educational estimate — principal & interest only. Your lender's schedule may differ due to fees, escrow, payment timing, and rounding.

Key takeaways

  • Your monthly payment is $1,580.17 for 30 years.
  • Over the loan you pay about $318,862 in interest — roughly 128% of the amount borrowed.
  • The first payment is mostly interest ($1,354.17) and only $226.00 principal; that flips as the balance falls.
  • Adding extra principal — even a small amount each month — would shorten the term and cut total interest; try it in the extra-payments section.

Visual breakdown

How the loan splits and shrinks over time. Each chart has a data table beneath it for exact figures and screen readers.

Cumulative principal vs interest

How much of what you have paid is principal versus interest, by year.

Over the loan you pay $250,000 of principal and $318,862 of interest.

Show data table
YearPrincipalInterest
2026$1,375$8,107
2027$4,261$24,182
2028$7,341$40,065
2029$10,626$55,741
2030$14,132$71,197
2031$17,873$86,418
2032$21,865$101,389
2033$26,123$116,092
2034$30,667$130,510
2035$35,515$144,624
2036$40,688$158,413
2037$46,207$171,856
2038$52,096$184,929
2039$58,379$197,608
2040$65,083$209,866
2041$72,237$221,675
2042$79,869$233,005
2043$88,012$243,824
2044$96,701$254,097
2045$105,971$263,789
2046$115,862$272,859
2047$126,416$281,268
2048$137,677$288,969
2049$149,692$295,916
2050$162,511$302,059
2051$176,189$307,343
2052$190,783$311,711
2053$206,355$315,102
2054$222,969$317,449
2055$240,696$318,684
2056$250,000$318,862

Balance over time

How the remaining balance falls toward zero.

The balance reaches zero at Jun 2056.

Show data table
YearBalance
0$250,000
1$247,206
2$244,224
3$241,043
4$237,649
5$234,027
6$230,163
7$226,041
8$221,642
9$216,948
10$211,940
11$206,597
12$200,896
13$194,813
14$188,323
15$181,398
16$174,009
17$166,126
18$157,714
19$148,739
20$139,163
21$128,946
22$118,045
23$106,413
24$94,002
25$80,761
26$66,632
27$51,557
28$35,473
29$18,311
30$0

Total interest vs principal

The cost of borrowing next to the amount borrowed.

You pay $318,862 interest on $250,000 borrowed.

Show data table
Amount
Principal$250,000
Interest$318,862

Amortization schedule

The first 12 payments are shown by default. Open the full schedule for payment-by-payment detail, or switch to the yearly summary. On phones the schedule shows as compact cards.

Monthly amortization schedule
#DateBeginningPaymentExtraPrincipalInterestEndingCum. interest
1Jul 2026$250,000$1,580.17—$226.00$1,354.17$249,774$1,354
2Aug 2026$249,774$1,580.17—$227.23$1,352.94$249,547$2,707
3Sep 2026$249,547$1,580.17—$228.46$1,351.71$249,318$4,059
4Oct 2026$249,318$1,580.17—$229.70$1,350.47$249,089$5,409
5Nov 2026$249,089$1,580.17—$230.94$1,349.23$248,858$6,759
6Dec 2026$248,858$1,580.17—$232.19$1,347.98$248,625$8,107
7Jan 2027$248,625$1,580.17—$233.45$1,346.72$248,392$9,453
8Feb 2027$248,392$1,580.17—$234.71$1,345.46$248,157$10,799
9Mar 2027$248,157$1,580.17—$235.98$1,344.19$247,921$12,143
10Apr 2027$247,921$1,580.17—$237.26$1,342.91$247,684$13,486
11May 2027$247,684$1,580.17—$238.55$1,341.62$247,446$14,827
12Jun 2027$247,446$1,580.17—$239.84$1,340.33$247,206$16,168
Monthly payment$1,580.17
Result

An amortization calculator shows how each loan payment is split between principal and interest over time — and how the balance falls to zero by the end of the term.

Quick answers

What is an amortization calculator?

An amortization calculator shows how each loan payment is split between principal and interest over time, and how the balance falls to zero by the end of the term. It produces the monthly payment, a full payment-by-payment schedule, a yearly summary, and the total interest you will pay — for any fixed-rate loan such as a mortgage, auto, personal, or student loan.

How is loan amortization calculated?

Each month, interest is charged on the current balance (balance × annual rate ÷ 12). The fixed payment covers that interest first, and the rest reduces the principal. As the balance falls, the interest portion shrinks and the principal portion grows, even though the payment stays the same, until the balance reaches zero at the end of the term.

How does an amortization schedule work?

An amortization schedule lists every payment with the interest paid, the principal paid, and the remaining balance. Early rows are mostly interest because the balance is large; later rows are mostly principal as the balance shrinks. The schedule on this page shows this month by month, with a yearly summary, so you can see exactly where each payment goes.

How do extra payments affect amortization?

Extra principal payments reduce the balance faster, so less interest accrues every following month and the loan ends sooner. Because interest is charged on the outstanding balance, extra payments made early save the most. This calculator models extra monthly, yearly, and one-time payments and shows the interest saved and the months knocked off the term.

Why is my early payment mostly interest?

Interest is charged on the outstanding balance, which is at its highest at the start of the loan. So in the first payments most of the money goes to interest and only a little to principal. As you pay the balance down, the interest charged each month falls and a larger share of the same fixed payment goes to principal.

What is the amortization formula?

The monthly payment is M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is the loan amount, r is the monthly interest rate (annual ÷ 12 ÷ 100), and n is the number of payments. At a 0% rate it simplifies to M = P ÷ n. Each month, interest = balance × r and principal = payment − interest.

What is the difference between amortization and APR?

The interest rate drives the monthly payment and the amortization schedule. APR (annual percentage rate) is broader: it folds the interest rate together with certain loan fees, expressed as a yearly rate, to make the true cost of two loan offers comparable. Use the interest rate for the schedule, and the APR to compare offers.

Does this amortization calculator include taxes and insurance?

No. It models principal and interest only, which is the part that amortizes. Property taxes, homeowners insurance, PMI, and HOA fees are often bundled into a mortgage payment but are not part of the amortization math. Add them separately if you want the full monthly housing cost; keep them out when comparing loan offers.

How accurate is an amortization calculator?

For a fixed-rate loan, the schedule is mathematically exact given the amount, rate, and term you enter, and the final payment is trimmed so the balance ends at exactly zero. Real lender schedules can differ slightly because of fees, payment-timing rules, compounding conventions, and rounding, so treat it as a close estimate and confirm with your loan documents.

Can I download the amortization schedule to Excel?

Yes. The Download Excel model button builds a multi-sheet .xlsx workbook from your live inputs — a summary, the full monthly schedule, a yearly summary, your extra-payment plan, the formulas, and a disclaimer with sources. The schedule cells use real Excel formulas, so the model recalculates if you edit the loan in the spreadsheet. It is generated in your browser, with no upload.

How to use this amortization calculator

  1. Enter the loan. Add the loan amount, the annual interest rate, and the term in years or months. The monthly payment and schedule appear instantly.
  2. Add any extra payments. Optionally add extra monthly, yearly, or one-time payments to see how much sooner the loan is paid off and how much interest you save.
  3. Read the results and schedule. Check the monthly payment, total interest, and payoff date, then open the yearly or full monthly schedule to see every payment split into principal and interest.
  4. Export to Excel. Download the 6-sheet Excel model to keep, share, or edit — the schedule recalculates in the spreadsheet if you change the loan.

The amortization formula

Monthly payment

M = P × r(1+r)ⁿ / ((1+r)ⁿ − 1)

P is the loan amount, r the monthly rate (annual ÷ 12 ÷ 100), n the number of payments. At a 0% rate it becomes M = P / n.

Interest each month

interest = balance × r

Interest is charged on the remaining balance, so it is highest at the start and falls as the balance drops.

Principal each month

principal = payment − interest + extra

Whatever is left of the payment after interest reduces the balance, plus any extra principal you add.

Ending balance

ending = MAX(0, balance − principal − extra)

The balance never goes below zero; the final payment is trimmed to clear the exact amount left.

How loan amortization works

What amortization is

Amortization is paying off a loan in equal, scheduled payments until the balance reaches zero. Every payment is the same size, but what it does behind the scenes changes each month: the share going to interest falls and the share going to principal rises.

The idea is to spread the cost of borrowing evenly across the term, so you always know what you owe while the lender earns interest on whatever balance is still outstanding.

How each payment splits and shifts

Every payment is divided in two. The first part covers the interest due on the current balance; whatever is left reduces the principal. Because the balance is largest at the start, the interest slice is biggest early on and the principal slice is small.

As the balance shrinks, less interest accrues, so the principal slice grows month after month — even though the total payment never changes. This is why the balance falls slowly at first and then faster toward the end.

Reading the monthly schedule

The monthly schedule lists each payment with the beginning balance, the interest paid, the principal paid, any extra payment, and the ending balance, plus running totals. The yearly summary rolls the same figures up by year.

Scanning down the columns tells the story: interest paid falls, principal paid rises, and the ending balance drops toward zero. On this page the schedule shows the first year by default — open the full schedule when you need payment-by-payment detail.

How extra payments shorten the loan

Interest is charged on the outstanding balance, which is at its peak in the early years. A dollar of extra principal paid early erases interest for every remaining year of the loan; the same dollar paid near the end saves almost nothing.

That is why even modest extra payments early on can cut the term and total interest substantially. Add an extra monthly amount, a yearly lump sum, or one-time payments to see the interest saved and the new payoff date.

Loan amortization vs accounting amortization

On a loan, amortization means gradually repaying the balance through scheduled principal-and-interest payments — the topic of this calculator.

In accounting, amortization is different: it means spreading the cost of an intangible asset (like a patent or software licence) across its useful life on the income statement, similar to depreciation for physical assets. Both spread a value over time, but loan amortization repays debt while accounting amortization expenses an asset.

When this calculator is useful

Use it to size up any fixed-rate loan before or after you borrow: to see the monthly payment, the true total interest, how fast you build equity, and what extra payments would do. It is handy for mortgages, auto loans, personal loans, and student loans, and for deciding whether to pay extra or refinance.

When this calculator may not match your lender

This models principal and interest with standard monthly compounding. A lender statement can differ because it bundles escrow (taxes and insurance), charges fees or PMI, applies payments on specific dates, uses a different day-count or compounding convention, or handles rounding its own way.

Adjustable-rate, interest-only, and balloon loans also behave differently once their structure kicks in. Treat this as a close planning estimate and rely on your loan documents for the exact figures.

Worked example

Take a $250,000 loan at 6.5% over 30 years.

Monthly payment

$1,580.17

First payment interest

$1,354.17

First payment principal

$226.00

Total interest

≈ $318,862

Total paid

≈ $568,862

Add $100/mo extra

≈ $58,000 saved, 4.7y earlier

At 6.5% you pay about $1,580 a month. The very first payment is roughly 86% interest and 14% principal, which is why the balance barely moves early on. Over 30 years the total interest (about $318,862) is larger than the original loan. Adding just $100 a month to principal pays the loan off about 4.7 years sooner and saves roughly $58,000 in interest — because that extra dollar erases interest for every remaining year of the loan.

Methodology & limitations

This calculator uses standard fixed-rate amortization with monthly compounding. Each month interest is charged on the balance, the fixed payment covers it first, and the remainder (plus any extra principal) reduces the balance. The final payment is trimmed so the balance ends at exactly zero, and extra payments are capped at the remaining balance so the schedule can only shorten, never go negative.

What it does not include: this calculator does not include lender fees, escrow, property taxes, insurance, late payments, variable or changing interest rates, balloon payments, or lender-specific compounding rules unless those options are explicitly entered as the rate, term, or extra payments above.

Frequently asked questions

What is amortization?

Amortization is the gradual reduction of a loan balance through scheduled payments. Each payment covers the accrued interest first, then reduces the principal. Because early payments are mostly interest, the balance falls slowly at first, then faster as the outstanding principal — and the interest charged on it — shrinks.

Why does my balance decrease so slowly at first?

Interest is charged on the remaining balance each month. On a $250,000 loan at 6.5%, the first month's interest is about $1,354 of a roughly $1,580 payment, leaving only ~$226 for principal. As the balance falls, less interest accrues and more of the fixed payment goes to principal, so balance reduction speeds up in the later years.

How much do extra payments really save?

It depends on the loan, but the effect is large early on. On a 30-year $250,000 loan at 6.5%, adding $100 a month to principal pays the loan off roughly 4.7 years early and saves about $58,000 in interest. Because interest is charged on the balance, every extra dollar paid early removes interest for all the remaining years.

What is the difference between the interest rate and APR?

The interest rate determines your monthly payment and the amortization schedule. The APR (annual percentage rate) folds the interest rate together with certain loan fees into one yearly figure, so it is a better measure of total cost when comparing offers. Lenders are required to disclose APR. Use the rate for the schedule and the APR to compare.

How do I read an amortization schedule?

Each row is one payment and shows the interest paid, the principal paid, and the balance left. Reading top to bottom, the principal column grows and the interest column shrinks as the balance falls. The yearly and monthly tables on this page do exactly this for your loan, with running totals of interest and principal.

What is the difference between amortizing and interest-only loans?

An amortizing loan includes principal in every payment, so the balance steadily falls and reaches zero at the end of the term. An interest-only loan covers just the interest for a period, so the balance does not move until principal payments begin. Amortizing loans cost more per month but build equity from day one.

Does this calculator include taxes, insurance, or fees?

No. It compares principal and interest only — the part that amortizes. Escrow items like property taxes and homeowners insurance, plus lender fees and PMI, are often bundled into a payment but are not part of the amortization math. Leave them out when comparing loan offers, and add them separately for a full monthly cost.

How accurate is this amortization calculator?

For a fixed-rate loan the math is exact given the amount, rate, and term, and the final payment is trimmed so the balance ends at exactly zero with no negative rounding. Lender schedules can differ slightly because of fees, payment-timing rules, compounding conventions, and rounding, so use this as a close estimate and confirm with your documents.

Can I add more than one one-time extra payment?

Yes. The extra-payments section starts with three one-time rows and lets you add up to ten, each with its own amount and month. Combine them with an extra monthly amount and a yearly lump sum; the engine applies each to principal on its date, caps it at the remaining balance, and stops the schedule the month the loan is paid off.

Can I download the result as Excel?

Yes. The Download Excel model button builds a 6-sheet .xlsx workbook from your live inputs: a summary, the full monthly schedule (with real Excel formulas), a yearly summary, your extra-payment plan, the formulas and methodology, and a disclaimer with sources. It is generated in your browser when you click, with no upload.

Related calculators

Amortization underlies most loans — these related tools build on the same math:

  • Loan CalculatorWork out the monthly payment, total interest, and payoff date for any fixed-rate loan from the amount, rate, and term.
  • Mortgage CalculatorEstimate monthly payments, interest, taxes, insurance, PMI, and amortization using practical home-loan assumptions.
  • Mortgage Payoff CalculatorSee how extra payments, lump sums, and biweekly payments change your mortgage-free date and total interest.
  • Mortgage Refinance CalculatorCompare your current mortgage to a new rate and term to see the monthly saving and how long it takes to break even.
  • Auto Loan CalculatorCalculate a car-loan payment from price, down payment, trade-in, rate, and term, including the total cost of financing.
  • Personal Loan CalculatorEstimate repayments on an unsecured personal loan and see how the rate and term change what you pay overall.
  • Debt Payoff CalculatorFind how long it takes to clear a debt and the total interest, based on your balance, rate, and payment.

Sources & methodology

This calculator uses standard fixed-rate amortization math. Loan amounts, rates, terms, and extra payments are user-entered; results are estimates, not a lender quote. Links open in a new tab.

Finance disclaimer

This calculator is for educational and planning purposes only. It is not financial, lending, tax, accounting, or legal advice and is not a lender quote. It models principal and interest using standard fixed-rate amortization math. Actual lender schedules can differ because of fees, escrow, payment timing, compounding conventions, prepayment rules, late payments, and rounding. Verify with your lender or loan documents before deciding.

Built and maintained by Calculator Matters, an independent calculator project. Method checked against standard amortization formulas and CFPB guidance · Updated June 8, 2026 · How we calculate · Found an error? corrections@calculatormatters.com