Student Loan Payoff Calculator
Payoff date, total interest and the effect of paying extra.
Enter your values
Enter the loan balance in $.
Enter the interest rate in %.
Enter the monthly payment in $.
Enter the extra payment in $.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Payoff time with extra payments
- 6 yr 11 mo
- Payoff time without extra
- 10 yr 5 mo
- Time saved
- 3.5 years
- Total interest with extra
- $9,273.56
- Interest saved
- $5,089.92
- Total paid
- $47,273.56
Quick answer
Extra payments go straight to principal, so every additional dollar removes all the future interest that dollar would have accrued.
n = −ln(1 − r × B ÷ P) ÷ ln(1 + r)
At a glance
| What it does | Payoff date, total interest and the effect of paying extra. |
|---|---|
| Category | Finance |
| Inputs needed | Loan balance, Interest rate, Monthly payment, Extra payment |
| Main output | Payoff time with extra payments |
| Formula | n = −ln(1 − r × B ÷ P) ÷ ln(1 + r) |
| Cost | Free — no sign-up, no download |
How to use the Student Loan Payoff Calculator
- 1Enter your total balance and weighted average rate.
- 2Enter the required monthly payment.
- 3Try different extra payments to see the time and interest saved.
Inputs explained
- Loan balance($)
- Enter the loan balance in $.
- Interest rate(%)
- Enter the interest rate in %.
- Monthly payment($)
- Enter the monthly payment in $.
- Extra payment($)
- Enter the extra payment in $.
Worked example
Using the values the calculator loads with:
Inputs
- Loan balance38000 $
- Interest rate6.5 %
- Monthly payment420 $
- Extra payment150 $
Results
- Payoff time with extra payments6 yr 11 mo
- Payoff time without extra10 yr 5 mo
- Time saved3.5 years
- Total interest with extra$9,273.56
- Interest saved$5,089.92
- Total paid$47,273.56
Frequently asked questions
Should I target the highest rate first?
Yes, mathematically — the avalanche method saves the most interest. The snowball (smallest balance first) wins on motivation if that keeps you going.
Do extra payments go to principal?
Only if you tell the servicer. Otherwise they may be applied as an advance payment on next month's bill, which saves far less.
What do I need to enter into the Student Loan Payoff Calculator?
Just 4 values: loan balance, interest rate, monthly payment, extra payment. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Student Loan Payoff Calculator work out the answer?
Extra payments go straight to principal, so every additional dollar removes all the future interest that dollar would have accrued. It applies the formula n = −ln(1 − r × B ÷ P) ÷ ln(1 + r) and shows the working so you can check each step by hand.
Is the Student Loan Payoff Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.