Loan Payoff Calculator

Why does an early extra payment save more interest?

A loan's interest is calculated each period on the remaining balance, not on the original amount. On a $10,000 loan at 7.5% with 48 months to go, the first month's interest is $62.50 of the $241.79 payment. An extra $100 paid that month is never charged interest again and saves $34.02 over the remaining 47 months.

That is $100 × (1.00625^47 − 1): the 7.5% a year that would have compounded on the $100.

The further along in the loan you are, the less the same dollar saves, because it has fewer months left in which to avoid interest. The same $100 paid in month 40 of the 48-month loan saves $5.10; paid in month 47 it saves $0.62. This is why financial educators say "pay extra early, not later": an early dollar avoids interest for every month that remains.

The chart in this calculator shows both balance curves. Notice how the accelerated curve diverges sharply in the first year and then the gap narrows proportionally toward the end — that divergence is the leverage at work.

What is the difference between my statement balance and my payoff amount?

Almost every payoff calculator gets this wrong because most users do not know there are two different numbers. Your <strong>statement balance</strong> is the principal remaining as of your last statement date. Your <strong>payoff amount</strong> is what it would cost to close the loan today, and it is always a little higher.

It is the statement balance plus per-diem interest accrued since the last statement, plus any fees your servicer charges.

Enter the statement balance into this calculator (the number labelled "principal balance" or "outstanding balance" on your statement), not the payoff amount. Using the payoff amount overstates your remaining principal and makes every projected payoff date too late. If you want to match your statement exactly, also enter the remaining term your statement shows.

When you are ready to actually close a loan, call your servicer for a formal payoff quote that specifies a payoff date — the quote is valid for a fixed window, typically 10–30 days, and the number on your statement is not.

How do the two solve modes work?

The <strong>"How long?"</strong> mode is the default. You enter what is on your statement — balance, rate, remaining term — and the calculator tells you the payoff date, plus the effect of any extra payment or lump sum. This is the right starting point for most people.

The <strong>"How much per month?"</strong> mode reverses the question: you pick a target payoff date and the calculator tells you the extra monthly payment needed to reach it. For example, a $10,000 balance at 7.5% with 48 months remaining has a base payment of $241.79. If you want to pay it off in 24 months instead, you need a total payment of $450.00 — an extra $208.21 per month.

Neither mode recommends a strategy. They show you the arithmetic under your assumptions. Whether paying extra is the right move depends on your interest rate relative to other uses of that money — the invest-instead comparison in the Advanced section puts both figures side by side for you to judge.

Should I pay off my loan early or invest the difference?

Paying off a loan early earns a <strong>guaranteed</strong> return equal to your loan's interest rate — for a 7.5% loan, every extra dollar saves 7.5% per year with certainty. Investing the same dollar in the stock market might earn more or less, with no guarantee.

The case for paying off first is strongest when: (1) your loan rate is high (credit cards at 20%+ beat almost any investment after tax); (2) you have no emergency fund; (3) the loan payment is a burden on cash flow; or (4) you are within a few years of retirement and want to eliminate the obligation. The case for investing is stronger when your loan rate is low (a 3% car loan from 2021), you have employer-matched retirement contributions not yet captured, or you carry no higher-rate debt.

This calculator shows both figures in the Advanced section. Enter your expected annual return and the invest-instead strip will appear below the results. The comparison uses the extra dollars you would have paid toward the loan — not your whole budget. The result is labelled illustrative because actual investment returns vary; the loan payoff number is exact under your inputs.

When does a prepayment penalty cancel the saving?

Most loans originated after 2014 carry no prepayment penalty, thanks to the Dodd-Frank consumer protections that restrict qualified mortgage penalties. However, some older personal loans, auto loans, and non-qualified mortgages still carry fees for early payoff, and a large enough fee can cancel the interest an extra payment saves.

Penalties come in three forms: a flat dollar fee (common in personal loans), a percentage of the remaining balance (common in older auto loans), or a number of months' interest (found in some private student loans and older mortgages). A three-month interest penalty on a $10,000 loan at 7.5% costs $187.50 — which can eliminate the advantage of a few months of extra payment.

The Advanced section of this calculator has fields for all three penalty types. Enter the penalty and the "net saving" KPI shows your real benefit. Check your loan agreement for the exact penalty clause; your servicer can also provide it in writing. If there is no penalty clause, leave the field at "None".