Student Loan Payoff Calculator

See when your student loan will be paid off and how much interest it will cost, then find how much faster an extra monthly payment clears the balance.

Start from a typical student-loan scenario
How do you want to plan it?
Display settings: currency symbol
Your loan is paid off in
Payoff time
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Total interest
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What the extra payment changes
Time saved
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Sooner than the plan without the extra amount.
Interest saved
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Money kept by clearing the loan faster.

How the balance falls to zero
Base plan With extra payment

Each curve tracks the remaining balance month by month. The steeper a curve drops, the faster the loan clears; the gap between the two is the time the extra payment removes.

For beginners: how to read this
Interest is taken firstEvery month the loan is charged interest on the balance. Only the part of your payment left after that interest actually shrinks what you owe.
Early money matters mostAn extra payment early on cuts the balance while it is still large, so less interest is charged for the rest of the loan. The same money added later saves less.
The payment must beat the interestIf your monthly payment is smaller than one month of interest, the balance grows instead of falling and the loan never clears. Raise the payment above that line.
Payoff time vs total interestA longer term means smaller monthly payments but more interest overall. A shorter term costs more each month but far less in total.
This is an estimate based on one fixed interest rate and equal monthly payments. Real student loans may use daily interest accrual, fees, capitalised interest after deferment, or income-driven plans. Check your loan agreement for the exact terms and confirm there is no prepayment penalty before adding extra payments.

To get a result, pick one of the starting scenarios or enter your own figures: your current loan balance and the annual interest rate stated on the loan. Then choose how you want to plan the payoff, and add an extra payment to see how much time and interest it saves.

Two ways to plan the payoff

The calculator works in two modes, switched with the planning toggle.

  • I pay a fixed amount: you enter the monthly payment and the tool works out how many years and months until the balance reaches zero.
  • I want to be done in X years: you enter a target time, for example clearing the loan five years after graduation, and the tool works out the monthly payment that hits that deadline.

How the payoff time is calculated

Each month the loan is charged interest on the remaining balance. The monthly rate is the annual rate divided by twelve. Only the part of your payment left after that interest reduces what you owe. The number of months to clear a balance from a fixed payment is found with months equals minus the natural log of one minus monthly rate times balance divided by payment, all divided by the natural log of one plus the monthly rate. To solve the other way, the payment needed for a set term is balance times monthly rate, divided by one minus one plus the monthly rate raised to the power of minus the number of months. Total interest is simply the total amount paid minus the original balance.

Why the extra payment matters

The extra monthly payment field is the heart of this tool. Money added early cuts the balance while it is still large, so less interest is charged across the rest of the loan. The result panel shows the base plan against the base plan plus your extra payment, with two clear figures: the time saved and the interest saved. The balance curve plots both paths falling to zero so you can see the gap the extra payment creates. A small extra amount each month often removes years from a student loan and saves a noticeable sum in interest.

The payment-too-small warning

If a monthly payment is smaller than one month of interest, the balance grows instead of shrinking and the loan never clears. When that happens the calculator shows a clear warning and the interest figure it would take to start making progress, rather than a payoff date that can never be reached.

What is not included

This is an estimate based on a single fixed interest rate and equal monthly payments. It does not model loan fees, daily interest accrual, interest that capitalises after a deferment, multiple loans consolidated together, income-driven repayment plans, forgiveness programs or any tax effects. Check your own loan agreement for the exact terms and confirm there is no prepayment penalty before adding extra payments. For a general, non-student debt you can use a generic loan payoff calculator instead; this tool is framed around student-loan repayment and the extra-payment savings comparison.