loan calculator

Payment Calculator

The Payment Calculator has two fixed-rate modes. Calculate Monthly Payment solves the equal monthly payment from loan amount, term years and months, and annual interest rate. Calculate Loan Term keeps the entered monthly payment and simulates how many whole months it takes to repay the balance, including total payments, total interest, payoff years, and a payment note.

Result

Solved value: Monthly payment = $1,687.71
Monthly payment: $1,687.71
Payoff months: 180
Payoff years: 15
Total payments: $303,788.46
Total interest: $103,788.46
What this means: Fixed-term estimate using equal monthly payments.

Scenario nameNotes

Save this result, then use saved scenarios to switch between assumptions.

Before you calculate

Use this calculator when you want to compare a fixed-term payment estimate with a fixed-payment payoff-time estimate using the same loan amount and entered rate. Use Loan Payment for the simpler amount-rate-years view, Amortization when you need a payment schedule, Interest Rate when the payment is known and the rate is unknown, APR when fees need a cash-flow-rate estimate, Credit Card Payoff for revolving-card payoff assumptions, and CFPB, Regulation Z, lender disclosures, or relevant local sources for real APR, Truth in Lending, approval, product, fee, tax, legal, or jurisdiction-specific questions.

Formula summary

The app rounds the payment count with termYears * 12 + termMonths and converts the entered Annual interest rate to a monthly decimal rate with annualRate / 100 / 12. In monthlyPayment mode, it solves PMT = P * m / (1 - (1 + m)^-n), where P is loan amount, m is monthly rate, and n is payment count; at 0 percent, PMT = P / n. Total payments equal the solved monthly payment times payment count, and total interest equals total payments minus loan amount. In loanTerm mode, the app first checks whether monthlyPayment is greater than first-month interest. If it is not, payoff fields return 0 with a warning note. Otherwise the helper simulates each month, adds interest, pays min(monthlyPayment, balance + interest), allows a reduced final payment, counts payoff months, sums total payments and total interest, and stops at a 12000-month safety cap.

Worked example

Example: fixed term, zero rate, and fixed payment

With the default fixed-term inputs, a $200,000 loan amount, 15 years, 0 months, and 6 percent annual interest rate become 180 monthly payments. The calculator reports a solved monthly payment of $1,687.71, $303,788.46 total payments, $103,788.46 total interest, 180 payoff months, 15 payoff years, and the note Fixed-term estimate using equal monthly payments. In the 5-year validation fixture, $25,000 at 7.5 percent reports a $500.95 monthly payment, $30,056.92 total payments, and $5,056.92 total interest. In the zero-rate fixture, $12,000 over 1 year divides into 12 payments of $1,000.00 with $0.00 interest. In fixed-payment mode, the default $2,000 payment repays the $200,000 balance in 139 months, or 11.58 years, with $277,951.56 total payments and $77,951.56 total interest.

The examples show the difference between solving a payment for a chosen term and solving payoff time for a chosen payment. They are mechanical fixed-rate estimates, not lender quotes, legal disclosures, product comparisons, tax answers, or personal borrowing advice.

Assumptions

The calculator models one fixed-rate monthly-payment scenario. It does not model variable rates, daily interest accrual, non-monthly schedules, skipped payments, extra payments, payment holidays, refinancing, late fees, balloon payments, escrow, taxes, insurance, lender credits, or product-specific contract rules.
The entered annual rate is the rate assumption used in the payment formula. It is not automatically a lender APR, legal disclosure rate, finance-charge classification, amount-financed disclosure, total-of-payments disclosure, or product comparison. A positive term is needed for fixed-term mode to be meaningful, and the fixed-payment mode reports whole payoff months with a smaller final payment when needed.
Scoped independent comparator checks pass 4 of 4 scoped fixtures for overlapping fixed-term payment, zero-rate payment, fixed-payment payoff time, total payments, and total interest outputs. CFPB APR guidance is needed before explaining entered rate versus lender APR; Regulation Z sections 1026.18 and 1026.22 plus APR table materials are needed before legal payment-schedule, total-of-payments, finance-charge, APR-determination, disclosure-accuracy, or Truth in Lending claims; and lender, FTC, state, local, Investor.gov, IRS, SEC, FCA, MoneyHelper, or product sources are needed before mortgage, auto-loan, student-loan, credit-card, annuity, pension, tax, legal, jurisdiction-specific, approval, underwriting, or regulated-product claims. Results are educational estimates, not financial, tax, legal, lending, credit, retirement-income, consumer-rights, regulatory, or personalised advice.

Common mistakes to avoid

Using the monthlyPayment field in the fixed-term mode as if it controls the result. In Calculate Monthly Payment mode, that field can be present in the form but the solved payment is driven by loan amount, term, and annual rate.
Setting a fixed monthly payment too low to reduce the balance. If the entered payment does not exceed first-month interest, the calculator returns zero payoff fields and a warning note instead of pretending the loan amortizes.
Reading this page as a lender quote, legal APR, full amortization schedule, mortgage payment, credit-card statement calculation, annuity-income result, tax answer, product approval, or borrowing recommendation. Those questions need product documents, official sources, or qualified advice outside this calculator.

Methodology and sources

This calculator is an original implementation based on documented formulas, app-specific assumptions, deterministic fixtures, edge cases, rounding policy tests, and internal validation. It is not copied from a single source.

Outputs are checked with deterministic fixtures, edge cases, rounding policy tests, and internal independent comparator checks where overlapping outputs are available. The result remains an educational estimate, not a quote, approval, tax answer, or personalised advice.

Formula version 2026.05.22-generic-payment-term-solver. The version marks the calculation logic and validation fixture set used for this estimate.

CFPB APR versus interest-rate guidance should be used when copy explains the difference between the entered payment interest rate and a lender APR.
CFPB Regulation Z sections 1026.18 and 1026.22 plus APR table materials should be used when copy discusses finance charges, amount financed, payment schedule, total of payments, APR determination, disclosure accuracy, or Truth in Lending terminology.
Investor.gov, IRS, SEC, FCA, MoneyHelper, lender disclosures, or relevant local regulator sources should be used before copy frames the generic payment math as annuity income, pension income, mortgage, credit-card, auto-loan, product-specific, tax, legal, or jurisdiction-specific guidance.

Estimate only

The result is educational and is not financial, tax, legal, lending, investment, or regulated advice. Real provider terms, fees, rates, taxes, and personal circumstances can change the final answer.

Formula and help: read the full payment calculator methodology notes.