Loan calculator

Amortization Calculator

An amortization calculator shows how each loan payment is split between principal and interest over time. Build a full schedule for monthly, biweekly, weekly, or semi-monthly payments, model extra payments to see your early payoff date, and compare scenarios side by side.

Full payment schedule Biweekly / weekly Extra-payment payoff Scenario comparison Excel model
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Principal & interest only, not a lender quote. Fees, escrow, and rounding can make a lender's schedule differ.

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.

Calculator

Loan amortization schedule

Build your loan amortization schedule

Enter the loan, choose a payment frequency, and optionally add extra payments. The full schedule, payoff date, and interest savings update instantly.

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

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

The core loan: amount, rate, term, start date, and payment frequency.

$

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 months · 360 monthly payments.

Used to label payment dates.

Standard monthly schedule — 12 payments/year.

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 per-period amount begins.

$

A lump sum once a year.

The yearly extra recurs in this calendar month.

One-time extra payments

$
$
$

Up to 10 one-time rows. Rows with a zero amount are ignored. Extra payments are capped at the remaining balance.

Lenders may apply extra payments differently — some require you to designate them as principal-only. Check your loan terms.

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: $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.

Loan payoff summary

Original loan$250,000
Interest rate6.50%
Term30 years
FrequencyMonthly
Monthly payment$1,580
Extra/period—
Payoff dateJun 2056
Total interest$318,862
Total paid$568,862
Interest saved—
Time saved—
First payment split$1,354.17 int / $226.00 prin
Final payment$1,580.55

Planning estimate only. Not a lender payoff statement, APR disclosure, or financial advice.

APR and fees estimateOptional — add fees to estimate APR impact

Estimate how loan fees affect the total cost of borrowing. Add any upfront fees and choose whether they are paid at closing or rolled into the loan.

This is not an official APR disclosure. Official APR requires day-count conventions, prepaid interest, and lender-specific fee categorizations not modelled here.
$

Lender fee charged to originate the loan.

%

Points paid to buy down the rate.

$

Processing, underwriting, or other fees.

Upfront fees reduce net proceeds; rolled-in fees increase the loan balance.

Monthly cost add-onsOptional — property tax, insurance, PMI, HOA

Add monthly ownership costs to see the total housing payment. These are separate from the amortization schedule — they do not affect how principal and interest are calculated.

$

Annual tax ÷ 12.

$

Annual premium ÷ 12.

$

Typically 0.5–1.5% of loan/year ÷ 12.

$

Homeowners association dues.

$

Any other recurring monthly cost.

The amortization schedule above uses only principal & interest. Add-ons are shown here for context; they do not affect principal reduction, interest calculations, or the payoff date.

Scenario comparison

Compare three strategies side by side: no extras, your current extra payment plan, and a shorter loan term.

Loan scenario comparison
MetricBase loan
No extra payments		With extras
Current plan		20-year term
No extra payments
Payment$1,580.17—$1,863.93
Total interest$318,862—$197,345
Total paid$568,862—$447,345
Payoff dateJun 2056—Jun 2046
Time saved vs base——10 years
Interest saved vs base——$121,517

Educational estimate. Shorter-term scenario uses the same rate and no extra payments. Payment amounts may differ from lender quotes.

Key takeaways

  • Your monthly payment is $1,580.17 for 360 periods (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 shifts as the balance falls.
  • Adding extra principal — even a small amount each period — 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.

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
Cumulative principal vs interest
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
Balance over time
YearBalance
0$250,000
5$234,027
10$211,940
15$181,398
20$139,163
25$80,761
30$0
35$0
40$0
45$0
50$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
Total interest vs principal
Amount
Principal$250,000
Interest$318,862

Annual interest paid

Interest paid each calendar year — highest in the first years, falls as the balance shrinks.

Interest payments peak in the first year and fall each year until payoff.

Show data table
Annual interest paid
YearInterest paidPrincipal paid
2026$8,107$1,375
2027$16,076$2,886
2028$15,882$3,080
2029$15,676$3,286
2030$15,456$3,506
2031$15,221$3,741
2032$14,971$3,991
2033$14,703$4,259
2034$14,418$4,544
2035$14,114$4,848

Amortization schedule

First 12 payments shown by default. Switch to yearly summary or show the full schedule. On phones: compact cards.

Payment-by-payment 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

At a glance

Formula shown
M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1); each period interest = balance × r, principal = payment − interest.
Scenario support
Compare base, extra-payment, and shorter-term plans side by side across monthly, biweekly, weekly, or semi-monthly frequencies.
Workbook export
6-sheet Excel (XLSX) export
Educational estimate
Planning support from the values you enter — not professional advice.

How to read your result

The payment stays fixed for the whole term, but the schedule underneath shows what it actually buys each period: interest on the current balance first, then whatever is left reduces principal. Early rows are interest-heavy because the balance is largest at the start; later rows are principal-heavy as the balance falls. The yearly summary rolls that up so you can see the trend without scrolling hundreds of rows, and the scenario table compares your base loan against an extra-payment plan and a shorter term side by side — the fastest way to see what a few hundred extra dollars a year is actually worth. Switch the frequency selector to biweekly or weekly to see a correctly computed per-period rate, not a simple half-payment split.

The amortization formula

Payment

M = P × r(1+r)ⁿ / ((1+r)ⁿ − 1)

P is the loan amount, r the period rate (annual ÷ periods per year ÷ 100), n the number of periods.

Interest & principal each period

interest = balance × r; principal = payment − interest + extra

Ending balance = MAX(0, balance − principal − extra) — never below zero.

Worked example

A $250,000 loan at 6.5% over 30 years produces a monthly payment of $1,580.17. The very first payment is $1,354.17 interest and just $226.00 principal — roughly 86% interest — which is why the balance barely moves early on. Over the full term, total interest comes to about $318,862, more than the original loan itself, for a total paid of about $568,862. 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.

Assumptions

  • For monthly frequency, interest is charged at annual rate ÷ 12; biweekly at ÷ 26; weekly at ÷ 52; semi-monthly at ÷ 24.
  • Biweekly mode computes a true annual-rate-÷-26 period rate over 26 payments a year — not simply half the monthly payment, which is what some lender "biweekly" programs actually do and saves no interest.
  • The fixed payment covers interest first; the remainder, plus any extra principal, reduces the balance.
  • The final payment is trimmed so the balance ends at exactly zero; extra payments are capped at the remaining balance.
  • Results are estimates from the values you enter — not a lender quote or schedule.

Limitations

  • Does not include lender fees, escrow, property taxes, insurance, late payments, or lender-specific compounding rules.
  • Does not model variable or changing interest rates, or balloon payments.
  • The APR estimator and monthly cost add-ons are optional planning aids, not official APR disclosures, and do not affect the schedule itself.
  • Results depend entirely on the values you enter.

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.

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 does biweekly amortization work?

Biweekly amortization uses a period rate of annual rate ÷ 26. With 26 payments per year you make the equivalent of 13 monthly payments instead of 12, with the extra amount going to principal. This calculator computes biweekly properly — it does not simply divide the monthly payment by two, which would give the wrong payment amount and understate savings.

What is PMI and when does it go away?

PMI (private mortgage insurance) is required on conventional loans when the down payment is below 20%. The lender cancels it automatically when the loan balance reaches 80% of the original home value, typically around year 9–11 on a 30-year loan at standard rates. Accelerated payments can get you to 80% LTV sooner and cancel PMI earlier. Use the schedule table to find the period when balance ÷ original value reaches 80%.

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 Refinance CalculatorCompare your current mortgage to a new rate and term — monthly saving and break-even time on closing costs.
  • 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.

Read the guides

For why early payments barely touch the balance, and how extra payments change that, see How Amortization Works: Principal, Interest, and Loan Balance Explained.

For how this schedule fits into the full cost of a home purchase, see Mortgage Payment vs Total Loan Cost: What Borrowers Often Miss.

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.

How we calculate · Found an error? email us

Learn more

How Amortization Works: Principal, Interest, and Loan Balance Explained

Why early loan payments barely touch the balance: how a fixed payment splits between interest and principal, and how extra payments cut total interest.

Read the guide

Authorship & verification

Written and maintained by

  • Formula and examples verified on 14 June 2026
  • Educational estimate only

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