Financial

Loan Calculator

Calculate loan payments and see how extra monthly principal changes payoff time and interest.

Calculator.net reference
Inputs
Defaults are prefilled so the result is visible immediately.
$
%
years
$
$
Results
The extra-payment path shows whether a small added principal amount is worth it.

Scheduled payment

$512.91

Financed amount

$25,000.00

Scheduled interest

$5,774.80

Payoff with extra

54 months

Interest with extra

$5,124.84

Interest saved

$649.96

First month principal

$335.83

Formula and Assumptions
Payment = P x r / (1 - (1 + r)^-n), then the balance is amortized month by month with optional extra principal.

The extra payment is applied directly to principal each month.

Origination fee is included in the financed amount so fees are not hidden from APR-style comparisons.

Reference Upgrade
Built from the Calculator.net model, with added context.

Live validation and instant result updates instead of a submit-only workflow.

Multiple decision metrics are shown together, not only the primary answer.

Formula notes and assumptions are visible on the page so the math is easier to audit.

Reference Model

Modeled after the input style and primary output on Calculator.net's Loan Calculator.

The page keeps the math in one place and exposes the assumptions beside the result.

Default inputs: loanAmount=25000, interestRate=8.5, loanYears=5, extraPayment=50, originationFee=0