Principal vs. interest
How much of everything you repay is the amount borrowed versus interest. Updates as you change the inputs.
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Student Loan Calculator
Estimate your federal or private student loan payment, compare repayment timelines, and understand how interest affects your total borrowing cost.
Estimated monthly payment
$265
Balance$25,000
Total paid$31,800
Interest$6,800
Repayment120 months
What is a student loan calculator?
A student loan calculator estimates what you will actually pay to borrow for school. Enter your balance, APR, and repayment term, and it returns your monthly payment, the total you will repay, and how much of that total is interest, so you can compare repayment plans before committing.
How it works
Payments are calculated with a standard amortization formula. Early in the loan, most of each payment goes to interest; as the balance falls, more goes to principal. A longer term lowers the monthly payment but leaves the balance outstanding longer, so you pay more interest overall.
M = P × [ r(1+r)^n ] / [ (1+r)^n − 1 ]
M = monthly payment
P = loan balance (principal)
r = monthly interest rate (APR ÷ 12)
n = total number of monthly payments
M = monthly payment
P = loan balance (principal)
r = monthly interest rate (APR ÷ 12)
n = total number of monthly payments
Worked example
For a $25,000 balance at 5.5% APR repaid over 120 months (10 years):
| Item | Amount |
|---|---|
| Loan balance | $25,000 |
| Monthly payment | ~$271 |
| Total interest paid | ~$7,546 |
| Total repaid over 10 years | ~$32,546 |
Ways to pay less overall
- Make extra principal payments, every dollar above the minimum cuts future interest and shortens the term.
- Choose the shortest term your budget can comfortably handle to minimize total interest.
- Pay accruing interest while in school so it doesn't capitalize onto your balance.
- Look into refinancing if you can qualify for a meaningfully lower rate, but weigh the loss of federal protections first.
Frequently asked questions
How is my student loan payment calculated?
From your balance, APR, and term using a standard amortization formula. Each payment covers that month's interest first, and the rest reduces principal.
Should I choose a shorter repayment term?
A shorter term raises the monthly payment but sharply cuts total interest. A longer term lowers the payment but costs more overall.
Do extra payments help?
Yes. Extra payments go straight to principal, which lowers the balance, reduces future interest, and shortens the payoff timeline.
What happens if I defer payments?
Interest often keeps accruing and can capitalize onto your principal, increasing the total owed and future interest charges.
Is income-driven repayment better?
It can ease cash flow by capping payments to a share of income, but it usually extends the term and can raise total interest.
Should I pay interest while in school?
If you can, yes, it prevents interest from capitalizing onto your balance and reduces long-term repayment costs.