Enter your current balance, rate, and monthly payment to see how many months are left and how much interest remains, plus what an extra payment would save.

How to Use the Loan Payoff Calculator

Enter the current balance, the annual rate, and what you're paying each month. Add an extra monthly amount only if you're considering paying more than that — leave it at zero to see the baseline payoff timeline on its own.

This isn't an amortization calculator working from a fixed term — it works backward from a payment you're already making, or considering, to find out how long the balance actually takes to clear and how much interest still lies ahead.

Month-by-Month, Not a Formula

Rather than solving a closed-form equation, the calculator simulates the loan one month at a time: it charges a month of interest on the current balance, applies the payment, and repeats until the balance hits zero, capped at 1,200 months as a safety limit. That's the same mechanical process a real loan statement follows — just run forward automatically instead of one line at a time.

monthly rate = annual rate ÷ 100 ÷ 12
each month: interest = balance × monthly rate
            balance = balance + interest − payment

If the payment doesn't even cover a month's interest, the balance never shrinks — it grows instead. The calculator catches that case and reports the minimum interest charge your payment needs to clear, rather than looping forever chasing a balance that's moving the wrong way.

What an Extra Payment Actually Buys

Run the $8,000, 9%, $250-a-month defaults and payoff lands a little over three years out — about 37 months — with roughly $1,250 in interest along the way. Bump that to $300 a month and both numbers drop hard: closer to 30 months and around $1,000 in interest, a seven-month, $250 difference from just $50 more a month.

Add anything above zero to the extra payment field and the calculator reruns the same simulation with the higher amount, then compares the two outcomes directly: months saved and interest saved, shown only once there's an extra payment to compare against. Because interest is charged on a shrinking balance, extra payments made early in a loan's life save disproportionately more interest than the same extra amount paid later — the sooner the balance drops, the less interest it ever gets the chance to accrue.

Even a modest, consistent extra payment tends to cut months off the payoff faster than borrowers expect, precisely because every dollar of it goes straight to principal instead of splitting between principal and interest the way a regular payment does.