Student Loan Calculator
A free student loan calculator that shows your monthly payment, total interest, and payoff time — plus how much an extra payment each month can save you. Works for federal, private, and education loans in any currency.
View year-by-year breakdown
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How to Calculate Student Loan Repayment
Four inputs give you a full repayment picture:
- Loan amount — the total principal you borrowed.
- Interest rate — your annual percentage rate (APR).
- Term — repayment length in years (standard is 10).
- Extra payment — optional, to see how much faster you clear the debt.
Where P = principal, r = monthly rate (APR ÷ 12), n = number of monthly payments. This is the same amortization formula banks use.
Principal vs Interest — the True Cost
Higher monthly payments, but you clear the balance fast and interest has little time to build. Best if you can afford it.
Lower monthly payments feel easier, but interest accrues for years longer — often adding thousands to the true cost.
The Power of Extra Payments
Every extra dollar goes straight to the principal, so less interest builds afterwards. A verified example from this calculator:
On a $30,000 loan at 6% over 10 years, adding just $100/month clears it in about 7 years and 2 months instead of 10 — saving roughly $3,046 in interest. Try your own numbers in the extra-payment field above.
Federal vs Private Loans
Federal loan rates are fixed by the government and usually lower, with income-driven repayment options. Private loan rates depend on your credit and can be variable. Always confirm your exact rate and terms before borrowing — the official Federal Student Aid site is the authoritative source for U.S. federal loans.
Frequently Asked Questions
How is my monthly student loan payment calculated?
It uses the amortization formula M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is principal, r is the monthly rate (APR ÷ 12), and n is the number of months. That's the fixed amount that clears the loan over your chosen term.
How does the loan term affect total interest?
A longer term lowers the monthly payment but raises total interest, since it's charged on the balance for more months. A shorter term costs more monthly but far less overall.
Do extra monthly payments really save money?
Yes. Extra payments reduce the principal directly, so less interest accrues after. On $30,000 at 6% over 10 years, an extra $100/month saves about $3,046 and ~2.8 years.
Does this work for federal and private loans?
Yes — the amortization formula applies to federal direct, private, and refinanced loans. Just enter the amount, annual rate, and term.
What's the difference between principal and interest?
Principal is what you borrowed; interest is the lender's charge. Each payment covers interest first, then reduces principal — which is why early payments are mostly interest.
Does it include grace periods or fees?
No. It models standard repayment from the first payment, without origination fees or grace-period interest. Unsubsidized loans may accrue interest earlier, so real cost can be a little higher.