When you start graduate school at least half-time, your federal undergraduate loans generally go into an automatic payment pause called in-school deferment, so you won’t owe monthly payments while you’re enrolled. That’s the short version of what happens to undergrad loans in grad school, but it’s not the whole story. Interest keeps accruing on most federal loans, private undergraduate loans follow entirely different rules written by your lender, and the choices you make during this window affect your total debt, your grace period after graduation, and your eligibility for forgiveness programs.
The Automatic Federal Deferment
Enroll at least half-time in a graduate program at an eligible school, and your federal undergraduate loans qualify for in-school deferment. That covers Direct Subsidized Loans, Direct Unsubsidized Loans, and Direct PLUS Loans first disbursed on or after July 1, 2008.1Federal Student Aid. In-School Deferment Request Older Federal Perkins Loans from undergrad also qualify, though no new Perkins Loans have been issued since the program expired in 2017.
The deferment usually starts on its own. Your loan servicer processes it once it receives enrollment information from your school, either directly or through the National Student Loan Data System.2eCFR. 34 CFR 685.204 – Deferment If your status doesn’t update automatically, you can submit an In-School Deferment Request form to your servicer.1Federal Student Aid. In-School Deferment Request
Half-time enrollment is defined by your school as at least one-half of its normal full-time workload.2eCFR. 34 CFR 685.204 – Deferment For a standard credit-hour program, that usually falls around 4.5 to 6 credit hours per term, but your registrar makes the call. Drop below half-time or take a leave of absence, and the deferment ends.
Interest Keeps Growing on Most Loans
The payment pause does not stop interest from accumulating. Whether your balance grows during grad school depends on which type of undergraduate loan you hold.
Subsidized Loans Don’t Grow
On Direct Subsidized Loans, the federal government pays the interest while you’re enrolled at least half-time, during the grace period, and during deferment.3Federal Student Aid. Subsidized and Unsubsidized Loans Your subsidized balance holds steady while you’re in grad school, even though graduate students themselves can no longer take out new subsidized loans.
Unsubsidized Loans Keep Accruing
Direct Unsubsidized Loans are where the math gets expensive. Interest accrues daily from the day the loan is disbursed and keeps accruing through deferment.3Federal Student Aid. Subsidized and Unsubsidized Loans The rate is fixed at whatever was set when you first borrowed.
A borrower with $30,000 in unsubsidized undergraduate debt at 5% accrues roughly $1,500 of interest per year. Over a three-year graduate program, that’s about $4,500 piled on top of the original balance. If you don’t pay the interest as it accrues, it capitalizes when deferment ends, meaning the unpaid interest is folded into your principal.4Aidvantage – Federal Student Aid. Interest and Taxes From that point you’re paying interest on interest.
Paying Interest Voluntarily
You can make voluntary interest payments during deferment to keep capitalization from happening. Even partial payments reduce what gets added to your principal later. If you pay at least $600 in student loan interest during the year, your servicer sends you Form 1098-E, and you can deduct up to $2,500 of student loan interest on your federal return.5Internal Revenue Service. Instructions for Forms 1098-E and 1098-T Most grad students on limited income fall well under the deduction’s income phase-out.6Internal Revenue Service. Publication 970, Tax Benefits for Education
When Pausing Payments Is the Wrong Move
The automatic pause sounds like a universal win, but it can hurt borrowers pursuing Public Service Loan Forgiveness or working toward income-driven repayment forgiveness. Months in deferment do not count toward the 120 qualifying payments PSLF requires. Three years of grad school on deferment is 36 months of potential PSLF credit lost.
You have the right to cancel the deferment and stay in repayment. Federal regulations explicitly allow a borrower granted an automatic in-school deferment to opt out and keep paying.2eCFR. 34 CFR 685.204 – Deferment On an income-driven repayment plan, a grad student’s low income can produce a monthly payment as low as $0, and a $0 IDR payment made while you’re working full-time for a qualifying public service employer still counts as a qualifying PSLF payment.
Two conditions matter here. You need full-time employment with a qualifying public service employer during school, and you need to contact your servicer to waive the automatic deferment. If you’re attending grad school full-time without a qualifying employer, waiving deferment won’t help PSLF, though payments can still move you toward the 20- or 25-year IDR forgiveness timeline.
The Grace Period Trap
Direct Loans come with one six-month grace period over the life of the loan. If you went straight from undergrad into grad school without using it, the grace period starts when you drop below half-time or finish your graduate program. If your grace period already elapsed after undergrad, there’s no second one waiting. Repayment restarts as soon as deferment ends.
This catches people who took a gap year or two. You finished college, let the six months run out, maybe made some payments, then enrolled in grad school. Your loans deferred during the program, but when you leave, payments resume right away.
Parent PLUS Loans Taken for Your Undergrad
If a parent borrowed a Direct PLUS Loan for your undergraduate education, their loan follows a different rule. A parent is eligible for deferment on a PLUS Loan first disbursed on or after July 1, 2008 while the student the loan was taken for is enrolled at least half-time.2eCFR. 34 CFR 685.204 – Deferment This deferment is not automatic. The parent must submit a Parent PLUS Borrower Deferment Request form to their servicer, with the school certifying your enrollment.7Federal Student Aid. Parent PLUS Borrower Deferment Request
Many families miss this and keep paying through the student’s grad years when they don’t have to. For a PLUS Loan first disbursed before July 1, 2008, this deferment isn’t available, and the parent would need to ask the servicer about other options such as forbearance.
Private Undergraduate Loans Follow Your Contract
Private student loans don’t follow federal deferment rules. What happens during grad school depends on the promissory note you signed. Some private lenders offer an in-school deferment or forbearance, but these are discretionary. Other contracts require interest-only payments or full payments throughout graduate study no matter your enrollment status.
If your lender does offer a pause, read the terms. Many cap the deferment at a set number of months, and interest almost always continues to accrue. Federal rules require private education lenders to disclose borrowing costs, interest rates, and fees before you’re obligated to repay.8Consumer Financial Protection Bureau. 12 CFR Part 1026 Regulation Z – Section 1026.46 Disclosure doesn’t equal favorable terms, though. If deferment isn’t in your contract, going back to school won’t create one.
Don’t Refinance Federal Loans Before Grad School
Refinancing federal undergraduate loans into a private loan to chase a lower rate is almost always a mistake if you’re heading into grad school. Once you refinance, you permanently lose in-school deferment, income-driven repayment, and every federal forgiveness program, including PSLF and IDR forgiveness.9Federal Student Aid. Should I Refinance My Federal Student Loans Into a Private Loan You also lose the interest subsidy on any subsidized loans.
Interest savings rarely justify giving up those protections right before a period when your income is likely to drop. A private lender has no obligation to pause your payments during school, and there’s no $0 IDR payment option if your income falls. If a lower effective rate is what you want, voluntary interest payments during deferment prevent capitalization and preserve every federal benefit you already have.