🌐 EN
English 繁體中文 Deutsch Français Español Italiano Nederlands Svenska Norsk Dansk Tiếng Việt Bahasa Indonesia

🏦 US Loan Calculator

Compare a fixed monthly payment with optional extra principal and a one-time fee.

Scheduled monthly outflow
—
Total cost including entered fee — Total interest — Payoff months — Interest saved —

The entered rate is a nominal assumption. APR can include fees; enter a one-time origination fee separately. CFPB: interest rate vs APR · CFPB disclosure guide

Amortization (first 12 months)

MonthPaymentInterestPrincipalBalance
GUIDE

Learn more

01

Calculator inputs

Loan amount is the principal that will enter the payment formula, not the purchase price or the cash you receive after a lender deducts a fee. Nominal annual rate is the contract interest-rate assumption you want the calculator to divide into twelve equal monthly rates. Loan term is entered in years; the tool multiplies it by twelve and rounds to a whole number of months. Monthly extra principal is the same added amount in every modeled month. Enter zero if you only want the scheduled plan. One-time origination fee is a separate dollar cost. The calculator adds it to total cost after building the schedule, so the fee does not earn interest and does not reduce the loan proceeds in this model. The form is intended for a positive loan amount, a nonnegative rate, a term from one through one hundred years, and nonnegative extra principal and fee amounts. Use the figures from an actual offer. If a lender withholds an origination fee from the amount disbursed, enter the full principal as the loan amount and remember that the cash you receive may be lower.

02

Payment formula

The scheduled payment follows M = P times r divided by 1 minus (1 + r) raised to negative n. M is the fixed scheduled payment, P is the entered loan amount, r is the entered annual percentage divided by 1,200, and n is the rounded number of months. When the entered rate is zero, the tool uses P divided by n instead. It then builds the result one month at a time. Monthly interest equals the opening balance times r. Scheduled principal equals M minus that interest, and the entered extra principal is added to the principal portion. The tool never subtracts more principal than the balance, so the final payment can be smaller than the displayed regular outflow. After principal is subtracted, the new balance becomes the next month's opening balance. Interest is accumulated from those unrounded internal values. The loop stops when the balance is effectively below half a cent, when the entered term ends, or if a payment cannot reduce principal. This is monthly compounding with equal periods, not a daily accrual calculation.

03

Worked example

Suppose you enter a $20,000 loan amount, a 5.5% nominal annual rate, a five-year term, $100 of monthly extra principal, and a $400 one-time origination fee. The formula produces a scheduled payment of $382.02. Because the result labeled scheduled monthly outflow adds the chosen extra amount, the page displays $482.02 for regular months. In month one, interest is $91.67 and principal is $390.36, leaving $19,609.64. The modeled loan reaches zero in month 47. That last payment is only $61.27 because the code limits principal to the balance still owed. Total modeled interest is $2,234.34. With no extra principal, the same entered principal, rate, and term produce $2,921.39 of interest over 60 months. The displayed interest saved is therefore $687.06. Total cost including the entered fee is $22,634.34, which is principal plus modeled interest plus $400. These figures come from the calculator's own monthly schedule before the page formats money to two decimal places.

04

Result fields

Scheduled monthly outflow is the formula payment plus your monthly extra-principal entry. It describes a normal modeled month, not a contractual minimum, and the final payment may be lower. Total cost including entered fee is loan principal plus interest generated by the extra-payment scenario plus the fee you typed. It is not the amount financed or the cash delivered to you. Total interest is only interest produced by the monthly balance calculation; it excludes the origination fee. Payoff months counts the schedule rows needed to bring the modeled balance to zero. Interest saved subtracts scenario interest from the interest on the same loan with no extra principal, and the display will not show a negative saving. The doughnut chart compares entered principal with scenario interest. The amortization table lists month, actual payment, interest, principal, and ending balance, but it deliberately displays only the first 12 rows even when payoff takes longer. All money shown on the page is rounded to cents, while the schedule uses fuller precision internally. None of these outputs includes late charges, optional products, insurance, taxes, or collection costs.

05

US loan types

This model best matches a US closed-end installment loan with a fixed rate, a fixed scheduled payment, and interest calculated monthly on the declining balance. An unsecured personal loan may fit that structure, but its origination fee might be withheld from proceeds rather than paid separately. An auto loan is secured by the vehicle, so the contract can also involve a lien, repossession rights, financed add-ons, and taxes or registration costs. Those items belong in the entered principal only if the lender actually finances them; this page does not calculate a vehicle deal. Student loans need extra care. Federal or private student debt may use repayment plans, deferment, capitalization, subsidies, or payment-allocation rules that this fixed schedule does not reproduce. A servicer may apply a payment to outstanding interest before principal. Mortgages also carry escrow, closing-cost, and disclosure structures outside this general loan model. Before using the result, identify the note's amount financed, interest method, payment frequency, maturity, security interest, and any balloon amount. If any of those differ from this page's assumptions, the lender's schedule controls.

06

Federal disclosures

The federal Truth in Lending Act is implemented by Regulation Z, which is administered by the Consumer Financial Protection Bureau. For covered closed-end consumer credit, the lender's disclosures are designed to present the cost and terms in a standard form before you become obligated. The terms can include the annual percentage rate, finance charge, amount financed, total of payments, payment schedule, late-payment terms, and whether the contract includes a prepayment penalty. APR is a credit-cost measure, not simply the note rate typed into this calculator. Certain finance charges can make APR differ from the interest rate even when the monthly payment is based on that rate. This calculator does not derive APR because it does not classify fees under Regulation Z or solve a rate from the amount financed and payment stream. Use the entered nominal rate to reproduce the contract's interest calculation, then compare the page's payment and totals with the lender's disclosure. A mismatch may mean the offer finances a fee, uses a different first-payment date, has daily accrual, includes an add-on, or follows another payment structure. State lending laws and regulator requirements may add protections beyond federal disclosure rules.

07

Fees and taxes

The origination-fee field is a cost comparison input, not part of the amortization formula. The tool adds the entered fee once to principal plus modeled interest. It does not increase principal, reduce net proceeds, or change the payment. If an offer finances the fee, include that financed amount in loan principal instead of relying only on the fee field. If the lender deducts the fee from proceeds, compare both the cash you receive and the full amount you must repay. Also check whether the disclosed finance charge and APR treat that fee as a credit cost; the label a lender uses does not by itself tell this calculator how the fee is classified. The page does not estimate federal, state, or local tax effects. US tax treatment depends on what the borrowed money funds and on the loan category. Interest tied to personal spending is often treated differently from qualified education, business, investment, or home-related interest, each of which has its own conditions and limits. Do not subtract an expected deduction from total interest here. Use the calculator's gross cost, keep the lender's interest statements, and apply the tax rules for the relevant filing year separately.

08

Offer comparison

Compare offers with the same loan amount, term, and extra-principal assumption. First enter each offer's note rate and fee exactly as quoted. Check scheduled outflow for monthly cash needs, then use total cost including fee and total interest to see why a lower payment is not automatically cheaper. A longer term can lower the formula payment while leaving interest to accrue for more months. A fee can also make two offers with similar rates cost different amounts. Do not type an advertised APR into the nominal-rate field unless it is also the rate used to calculate the scheduled payment. APR and the contract interest rate answer different questions. For an early-payoff comparison, confirm that the lender accepts extra principal, whether you must give principal-only instructions, and whether an overpayment merely advances the next due date. Ask about any prepayment charge before treating the displayed saving as available. Run a zero-extra baseline and a realistic extra amount rather than an amount you cannot sustain. Finally, compare the first table row with the lender's schedule. A different interest amount is a quick sign that the lender uses daily accrual, a financed charge, or another balance convention.

09

Model limits

The calculation assumes the rate never changes, payments occur in equal monthly periods, every payment arrives on time, and the same extra principal is paid each month until payoff. It has no calendar, so it cannot reflect month length, the number of days between funding and the first payment, weekends, payment posting time, or daily simple interest. It does not model precomputed interest, interest-only periods, deferred payments, negative amortization, variable rates, balloon payments, biweekly drafts, lump-sum extras, recasting, refinancing, or forgiveness. The schedule also ignores late fees, returned-payment fees, optional insurance, collateral costs, and legal or collection charges. The fee entry is not tested for APR treatment and never affects interest. Terms above 1,200 months and invalid negative inputs produce blank result marks. The visible term field is capped at 100 years, and the schedule itself will not run beyond the entered month count. The page shows only the first 12 rows, so use payoff months and totals for the rest of the projection. Treat the result as a check on a fixed monthly scenario, not a payoff quote. A lender's dated payoff statement can include accrued interest and other amounts this model cannot know.

Frequently asked questions

Does the extra payment always reduce principal?
Inside this calculator, yes. The full extra amount is added to principal every modeled month, after that month's interest is calculated. A real US lender or servicer may first cover outstanding interest or fees, or may advance your due date unless you give principal-only instructions. Check the contract and payment screen before assuming the modeled payoff date applies.
Should I enter the interest rate or APR?
Enter the nominal annual rate used to calculate the loan's scheduled payment. Do not substitute APR unless the contract also uses that same rate for interest. APR may include certain finance charges and is meant for broader cost comparison. This page adds one fee to total cost but does not calculate an APR from it.
Why is the last payment smaller?
The tool adds the regular scheduled payment and your extra principal in each month, but it will not pay more principal than the remaining balance. In the payoff month, actual payment equals that smaller principal balance plus the month's interest. The headline monthly outflow still shows the normal scheduled amount plus extra, not the reduced final payment.
Does the origination fee change the payment?
No. The entered fee is added once to displayed total cost after the amortization schedule is complete. It does not change principal, interest, or monthly payment. If the lender finances the fee, add the financed portion to the loan amount. If the fee is withheld, compare the lower net proceeds with the full debt you repay.
Why does my lender show different interest?
This tool charges one-twelfth of the entered annual rate against each monthly opening balance. A lender may accrue simple interest by day, use a different first-payment interval, apply a payment on another date, or include financed charges in principal. Compare the contract's interest method and opening balance with month one in this table before relying on later rows.
Can I use this for a student loan?
Only as a simplified fixed-payment comparison. Student loans can have income-linked payments, deferment, subsidies, capitalized interest, forgiveness rules, and servicer allocation instructions that are absent here. If your loan has a fixed balance, rate, and term, the result can be a rough cross-check, but your servicer's required payment and payoff statement remain the controlling figures.
Why are only 12 months shown?
The JavaScript calculates rows through payoff or the entered term, but the page renders only the first 12 rows in the table. Total interest, total cost, payoff months, and interest saved use the full internal schedule. The short table is for checking the opening balance pattern, not for listing every future payment.
TRUST & SOURCES

Methodology and official sources

the US loan calculation explains its inputs, assumptions, and calculation scope.

Official status
Reference calculator; it does not make an official determination.
Effective date
Last reviewed

Method

It applies the disclosed APR, principal, term, and payment-frequency assumptions to the entered values.

Worked example

$10,000 at 8% APR for 36 months produces the displayed monthly-payment estimate.

Limitations

  • Rates, rules, and individual circumstances can change the result.

Sources