Student Loan Calculator
List every loan once and see the combined payment, the payoff date, and how much an extra payment saves when it goes to the highest rate first.
| Monthly payment | $381.32 + $100.00 extra |
|---|---|
| Total borrowed | $35,000.00 |
| Weighted average rate | 5.579% |
| Paid off in | 7 years, 5 months |
| Total interest | $7,500.70 |
| Interest saved by paying extra | $3,257.79 |
| Loan 1 ($12,000.00 at 5.5%) | $130.23/month |
| Loan 2 ($8,000.00 at 6.8%) | $92.06/month |
| Loan 3 ($15,000.00 at 4.99%) | $159.02/month |
How to use it
- Type one loan per line: the balance, a space, then the interest rate. You can paste the list from your loan servicer.
- Pick the repayment term. Ten years is the federal standard plan.
- Add any extra amount you can pay each month. It goes to the highest-rate loan first, and when a loan is paid off its payment rolls to the next one.
Formula
Each loan's payment M = P × i ÷ (1 − (1 + i)^−n), i = rate ÷ 12, n = years × 12Weighted average rate = Σ(balance × rate) ÷ Σ balance- Each month: interest = balance × i on every loan; extra and freed-up payments go to the highest rate
Example
Three loans of $12,000 at 5.5%, $8,000 at 6.8% and $15,000 at 4.99% on a 10-year plan cost $130.23 + $92.06 + $159.02 = $381.32 a month. The weighted rate is 5.579%. Adding $100 a month to the 6.8% loan first clears everything in 7 years, 5 months, with $7,500.70 of interest, $3,257.79 less than the standard plan.
Questions
Does this cover income-driven repayment?
No. Income-driven plans base the payment on income and family size, and the rules have changed several times. Check the Loan Simulator at studentaid.gov for those plans.
Why pay the highest rate first?
Every extra dollar on the highest-rate loan avoids the most interest. This is called the avalanche method.
Should I refinance federal loans into a private loan?
A private refinance can lower the rate but gives up federal options such as income-driven plans and forgiveness programs. Compare carefully first.
Related calculators
Last reviewed 2026-10-11. Found a mistake? Tell us.