Student Loan Payoff Calculator

Q: Can I use this if I have more than one student loan?

Yes. Two ways: Best: run the tool once per loan, since each has its own rate. Quick: add all balances and use an average rate for a rough total.

Q: What is the difference between Total Interest Paid and Total Repaid?

Total Interest Paid is the extra fee you pay the lender. Total Repaid is your loan balance plus that interest, the full amount that leaves your bank account.

Updated Sep 1, 2026 By Jehan Wadia

Introduction

This Student Loan Payoff Calculator shows you when your loan will be gone and how much interest you will pay. Put in your balance, your interest rate, and your monthly payment. Then add an extra amount each month and watch what happens.

The tool gives you two side-by-side answers. Scenario A is your plan today. Scenario B adds your extra payment. You will see both payoff dates, the total interest for each, and how much money and time you save by paying more. If you want to start with a standard repayment schedule instead, try our Student Loan Calculator.

Charts and a step-by-step breakdown show the math behind the numbers, so you can see exactly how extra payments cut down your loan. Move the sliders to test different payments and find a plan that works for your budget.

How to use our Student Loan Payoff Calculator

Enter four details about your student loan, and the calculator shows your payoff date, total interest, total repaid, and how much time and money an extra payment saves you.

Current Loan Balance: Type the amount you still owe today. Use the principal from your latest loan statement, not the original loan amount.

Annual Interest Rate (%): Type your loan's yearly interest rate, or drag the slider. You can pick any rate from 0% to 25%.

Monthly Payment: Type what you pay each month, or use the slider. This must be more than your monthly interest charge, or the balance will never drop.

Extra Monthly Payment: Type any extra amount you can add each month, or drag the slider. Put $0 if you pay nothing extra. Slide it up to see how much faster your loan is gone.

Click Calculate to see your results, charts, and the step-by-step math. Click Start Over to clear the form and try new numbers.

Understanding Student Loan Payoff

A student loan has two parts: the principal (the money you borrowed) and the interest (the fee the lender charges you for borrowing). Every month, interest is added to what you owe. Your payment first covers that interest. Whatever is left over goes toward the principal and lowers your balance.

How Interest Builds Each Month

Most student loans use simple daily or monthly interest. To find one month of interest, take your balance, multiply it by your yearly rate, and divide by 12. For example, a $24,500 balance at 6.5% costs about $132.71 in interest in the first month. If you pay $285, only about $152 goes to the principal. As the balance drops, the interest charge drops too, so more of each payment starts attacking the principal. You can check any single month's charge with the Monthly Interest Calculator.

Why Extra Payments Work So Well

Extra money goes straight to the principal. A smaller principal means less interest next month, and every month after that. This snowball effect is why even $50 or $100 extra a month can cut years off your loan and save thousands of dollars in interest. The earlier you start extra payments, the more you save, because the balance is biggest at the start.

Tips for Paying Off Student Loans Faster

Tell your servicer to apply extra money to the principal, not to future payments. Otherwise they may just move your due date.
Attack the highest rate first if you have several loans. That saves the most money. Map it out with the Debt Avalanche Calculator.
Round up your payment. Turning $285 into $300 costs little but helps a lot.
Use windfalls. Tax refunds, bonuses, and gifts make great one-time principal payments.
Check for penalties. Federal student loans have no prepayment penalty, and most private loans don't either.

Things That Change Your Payoff Date

Your payoff date depends on three numbers: your balance, your interest rate, and your monthly payment. Raising the payment shortens the loan. A higher rate stretches it out. If your payment is less than the monthly interest, your balance actually grows. That is called negative amortization, and it is a sign you need a bigger payment or a different repayment plan.

Before You Pay Extra

Paying off debt early is smart, but keep a small emergency fund first and grab any employer 401(k) match you can get. If your loan rate is low, splitting money between saving and extra payments can make sense. If your rate is high, putting extra cash toward the loan is usually the better deal.

Formulas used

Monthly interest rate from annual rate

i = \frac{r\%}{12 \times 100}

Monthly interest charge on current balance

I_{\text{month}} = B \times i

Amortization step (principal portion and new balance)

B_{k} = B_{k-1} - \left(P - B_{k-1} \times i\right)

Number of months to pay off the loan

n = \frac{-\ln\!\left(1 - \frac{i \times B}{P}\right)}{\ln(1 + i)}

Standard 10-year (120-month) payment

P_{\text{std}} = \frac{B \times i}{1 - (1 + i)^{-n}}, \quad n = 120

Total interest and total repaid

\text{Interest} = \text{Total paid} - B, \qquad \text{Total paid} = B + \sum_{k} B_{k-1} \times i

Savings from the extra payment

\text{Interest saved} = \text{Interest}_A - \text{Interest}_B, \qquad \text{Months saved} = n_A - n_B

Interest share of total repayment

\text{Interest \%} = \frac{\text{Interest}}{\text{Total paid}} \times 100

Frequently asked questions

Where do I find my current balance and interest rate?

Log in to your loan servicer's website or read your latest statement. Federal loan details are also listed at StudentAid.gov. Use the current payoff balance, not the amount you first borrowed.

Can I use this if I have more than one student loan?

Yes. Two ways:

Best: run the tool once per loan, since each has its own rate.
Quick: add all balances and use an average rate for a rough total.

Does this work for both federal and private student loans?

Yes. The math is the same for both. It also works for fixed-rate loans of any kind, like car loans or personal loans.

What is the difference between Total Interest Paid and Total Repaid?

Total Interest Paid is the extra fee you pay the lender. Total Repaid is your loan balance plus that interest, the full amount that leaves your bank account.

What does the standard 10-year payment mean?

It is the payment that would clear your balance in exactly 120 months at your rate. It is the default plan for federal loans, so it is a handy target to compare against.

How much can an extra $50 a month really save?

On a $24,500 loan at 6.5% paying $285 a month, adding $50 saves about $1,800 in interest and clears the loan about 23 months sooner. Type your own numbers to see your result.

Will paying extra lower my monthly bill?

No. Extra payments shorten the loan, they do not shrink your required payment. Your bill stays the same until the loan is gone. To lower the bill you would need to refinance or change plans.

Is a one-time lump sum the same as paying extra each month?

Not the same. A lump sum paid early kills more interest per dollar. To test one, subtract it from your balance and run the numbers again.

What if I can only pay extra in some months?

Use an average. Add up the extra money you expect to pay in a year and divide by 12. Type that in the extra payment box.

Should I pay extra if I am going for loan forgiveness?

Usually no. If your loans will be forgiven through PSLF or an income-driven plan, extra payments just hand over money you did not have to pay. Pay the required amount and save the rest.

Does interest keep growing if I pause my payments?

On most loans, yes. Interest still builds during deferment or forbearance and is often added to your balance when payments restart. Enter that new balance here.

Why does my loan take longer than 10 years in the results?

Your payment is smaller than the standard 10-year amount. Raise the monthly payment or add an extra payment, and the months drop fast.

Why is my last payment smaller than the others?

The final payment only covers what is left. The calculator rounds up to a whole month, so the last month is almost always a partial payment.

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