Student Loan Calculator
Estimate your student loan payment and total interest, including what happens while you’re still in school. Set a grace period and toggle whether interest accrues during school (unsubsidized) to see the capitalized balance you’ll actually start repaying.
Principal vs. interest
How your rate compares
Your rate vs. the 2025-26 federal undergraduate rate
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See ratesWhy the balance can grow before you make a single payment
If your loan is unsubsidized, interest starts accruing from the day it’s disbursed — while you’re still in school and through your grace period — even though you owe nothing yet. That unpaid interest doesn’t vanish: it capitalizes, meaning it’s added to your principal the moment repayment begins. From then on you’re paying interest on a bigger number, which is why the balance on your first bill is often noticeably higher than what you originally borrowed. Subsidized federal loans avoid this because the government covers interest during school and the grace period, so the balance you start repaying is exactly what you borrowed.
How it’s calculated
If interest accrues in school, unpaid interest is estimated as principal × monthly rate × months (simple, non-compounding accrual, matching standard federal loan treatment), separately for the in-school period and the grace period, then both are added to principal at repayment start — that sum is the capitalized balance. The standard amortized payment is then Payment = Balance × r ÷ (1 − (1 + r)−n), with r the monthly rate and n the number of monthly payments in the repayment term.
Results update as you type and are estimates for education, not financial advice — verify your exact terms, fees, and capitalization rules with your loan servicer.
Yearly repayment schedule
Shows interest paid, principal paid, and remaining balance for each year of repayment, starting from the capitalized balance.
Worked example
A $30,000 unsubsidized loan at 6.39%, with 4 years left in school and a standard 6-month grace period, accrues $7,668.00 in school and $958.50 during the grace period — capitalizing to a $38,626.50 starting balance. Repaid over 10 years, that’s $436.44 a month, with $13,745.98 in interest from repayment start ($22,372.48 total interest including what capitalized). The same loan with no in-school accrual (subsidized) would only need $338.97 a month on the original $30,000.
Common mistakes
- Assuming your payment will be based on the amount you originally borrowed — if interest accrued while you were in school, your real starting balance is higher.
- Ignoring the grace period entirely, which still accrues interest on unsubsidized loans even though no payment is due yet.
- Comparing a federal loan's fixed rate directly to a private loan's variable rate without accounting for the risk that a variable rate can rise over a 10-year term.
Where it is used
- Estimating your first student loan bill before you’ve graduated or left school.
- Understanding how much a subsidized vs. unsubsidized loan really costs over the same term.
- Budgeting for the jump from a grace-period balance to a fully capitalized repayment balance.
Frequently asked questions
What does "capitalized interest" mean?
It's unpaid interest that accrued while you were in school or in your grace period, added to your principal balance once repayment begins. From that point on, you pay interest on the new, larger balance — meaning interest earns interest, which is why unsubsidized loans can grow noticeably between disbursement and your first bill.
What's the difference between subsidized and unsubsidized loans?
The federal government pays the interest on subsidized loans while you're in school and during your grace period, so the balance doesn't grow. Unsubsidized loans accrue interest the entire time — it just isn't billed to you until capitalization at repayment start. Toggle "interest accrues in school" off to model a subsidized loan.
How long is a typical grace period?
Six months for most federal Direct Subsidized and Unsubsidized Loans after you graduate, leave school, or drop below half-time enrollment. Some private loans use a similar six-month window, but always confirm the exact terms in your loan documents.
Does this calculator include origination fees?
No — it models principal, interest accrual, and capitalization only. Federal Direct Loans carry a small origination fee deducted from the disbursement, which slightly reduces the cash you actually receive relative to the amount you owe; check studentaid.gov for the current fee schedule.
What's the current federal student loan interest rate?
For the 2025-26 academic year, new federal Direct Unsubsidized and Subsidized Loans for undergraduates carry a fixed rate of 6.39%, per the U.S. Department of Education. Rates are set annually each July and are fixed for the life of that year's loans — a loan disbursed in an earlier year keeps its original rate.