Loans

Loan Calculator

Estimate monthly payment, total payment, and total interest for a fixed-rate loan.

Payment = P × r / (1 - (1 + r)^-n)

What this calculator does

Calculate the level monthly payment, total repayment, and total interest for a fixed-rate fully amortizing loan with no fees.

Scope, period, and currency

This page runs a local formula from user-entered values. The country/currency selector changes money symbols and formatting only: it does not perform live or historical FX conversion or automatically change contract, tax, accounting, or regulatory rules. Convert all amounts into one currency first and keep periods and metric definitions consistent.

Formula variables

P: Loan principal.
i: Nominal annual interest rate.
r: Monthly rate = i ÷ 12.
n: Number of monthly payments; entered years are rounded to whole months.

Formula and worked example

Formula: Payment = P × r ÷ [1 − (1 + r)^−n]. At 0% interest, payment = P ÷ n.

Recalculation: $25,000 principal at 8.5% for 5 years gives 60 payments of $512.91, total repayment $30,774.80, and total interest $5,774.80.

Model assumptions

The rate is fixed and payments are made monthly at period end.
There are no origination fees, taxes, insurance, irregular first periods, or prepayment changes.
The displayed interest rate is not an APR calculation.

Reading the result and model boundary

Monthly payment shows scheduled principal and interest only.
Total interest is valid only if every scheduled payment is made and the rate remains fixed.

The model covers a regular fixed-rate amortizing loan, not variable-rate, interest-only, balloon, or irregular-payment contracts.

How to use it

Enter principal, nominal annual rate, and term.
Confirm the contract uses monthly fully amortizing payments.
Compare the result with the lender's APR, fees, and repayment schedule.

Common incorrect uses

Treating the nominal rate as APR.
Ignoring origination fees and required insurance.
Comparing monthly payment without comparing total cost and term.

Suggested verification workflow

Calculate principal-and-interest payment.
Add fees and other contract costs separately.
Compare against the formal disclosure and amortization schedule.

FAQ

Does the payment include fees or insurance?

No. It includes principal and interest from the entered rate only.

Is the entered interest rate APR?

Not necessarily. APR can include certain fees and uses disclosure rules not implemented here.

Does currency selection convert the loan?

No. It changes display formatting only; all money inputs must use one currency.

Method and review boundary

Results are calculated locally in the browser from the formula shown on this page. The tool does not retrieve live rates, quotes, approvals, or billing data. Last reviewed: July 24, 2026.

Use the result for first-pass estimates, scenario comparison, and question preparation; it is not financial, investment, tax, accounting, or legal advice.

Authoritative sources and notes

Regulation Z Appendix J - Consumer Financial Protection Bureau
Interest rate and APR - Consumer Financial Protection Bureau
How to compare loan offers - Consumer Financial Protection Bureau

Sources checked July 24, 2026. Rates, product rules, and official guidance can change; verify them again before a formal decision.