Both subsidized and unsubsidized federal student loans charge interest. The difference is who pays it while you’re in school: on a Direct Subsidized Loan, the U.S. Department of Education covers the interest during enrollment, your grace period, and any approved deferment; on a Direct Unsubsidized Loan, interest accrues from the day the money is disbursed and every dollar is yours.1Federal Student Aid. Subsidized and Unsubsidized Loans Over a four-year degree, that single distinction can add thousands to what you eventually repay.
What the Subsidy Actually Covers
Direct Subsidized Loans are available only to undergraduates who demonstrate financial need on the FAFSA, and your school sets the amount based on that need. The federal government pays the interest during three specific periods: while you’re enrolled at least half-time, during the six-month grace period after you leave school, and during any approved deferment.1Federal Student Aid. Subsidized and Unsubsidized Loans
The practical effect: your principal stays frozen across those stretches. For most borrowers, the balance owed when repayment begins equals the amount originally disbursed.
Why Unsubsidized Interest Is a Different Animal
Direct Unsubsidized Loans are open to both undergraduate and graduate students, and there’s no financial-need test. The government pays none of the interest. You owe it during school, during the grace period, and during any deferment or forbearance.1Federal Student Aid. Subsidized and Unsubsidized Loans
You aren’t required to make payments while enrolled, but interest doesn’t pause just because you aren’t paying. It accumulates daily from the moment funds hit your school’s account. By graduation, several years of unpaid interest may be sitting on your loan.
Graduate and professional students only have access to unsubsidized loans; they can’t borrow subsidized ones at all.2Federal Student Aid. 2025-2026 Federal Student Aid Handbook – Annual and Aggregate Loan Limits They also carry a higher interest rate, which makes the accrual problem sharper.
The Periods Where the Difference Shows Up
In School
Subsidized loan balances stay flat while you’re enrolled at least half-time because the government covers the interest.1Federal Student Aid. Subsidized and Unsubsidized Loans On unsubsidized loans, interest accrues daily. A $10,000 unsubsidized loan at 6.39% adds about $1.75 a day. Over four years, that’s roughly $2,557 in accrued interest before your first payment is even due.
The Grace Period
After you graduate, drop below half-time, or leave school, a six-month grace period starts before payments begin. On subsidized loans, the subsidy holds and interest still doesn’t accrue.1Federal Student Aid. Subsidized and Unsubsidized Loans On unsubsidized loans, the daily interest keeps piling on.
Deferment
Deferment is an approved payment pause, commonly granted for returning to school, economic hardship, or active military service. Interest does not accrue on subsidized loans during deferment because the government continues to pay it.1Federal Student Aid. Subsidized and Unsubsidized Loans It does accrue on unsubsidized loans, and you owe it.3Federal Student Aid. Deferment and Forbearance
Forbearance
Forbearance is where the subsidized loan loses its edge. Interest accrues on all federal loan types during forbearance, subsidized ones included.3Federal Student Aid. Deferment and Forbearance If you have a choice between deferment and forbearance and you qualify for deferment, take deferment.
Capitalization: When Interest Becomes Principal
Unpaid interest doesn’t stay a separate bucket forever. When it capitalizes, it gets added to your principal balance, and future interest then accrues on the higher amount. You end up paying interest on interest.4Consumer Financial Protection Bureau. How Does Interest Accrue While I Am in School?
For unsubsidized loans, this typically happens when your grace period ends or a deferment concludes.5Nelnet. Interest Capitalization A quick illustration: borrow $5,000 in unsubsidized loans at 10% for a 12-month program, and by the end of school plus the six-month grace period you’ve accumulated $750 in interest. That $750 folds into your principal, giving you a new balance of $5,750, and every future interest calculation runs on that larger number.4Consumer Financial Protection Bureau. How Does Interest Accrue While I Am in School?
Subsidized borrowers are largely shielded from this during school, grace, and deferment because no interest accrues to capitalize. Forbearance is the exception: interest that builds on a subsidized loan during forbearance can capitalize when the forbearance ends.
How Interest Is Calculated Day by Day
Federal student loans use a simple daily interest formula, not compound interest. Take the outstanding principal, multiply by the interest rate divided by 365, and you have the daily interest charge.6Federal Student Aid. Interest Rates and Fees for Federal Student Loans On a $10,000 loan at 6.39%: $10,000 × (0.0639 ÷ 365) = about $1.75 per day, or roughly $52.50 in a 30-day month. The daily figure holds steady until your principal changes, whether from a payment or from capitalization.
Current Rates and Fees
Rates are fixed for the life of each loan and set annually. For loans first disbursed on or after July 1, 2025, and before July 1, 2026:
- 6.39% for Direct Subsidized and Direct Unsubsidized Loans to undergraduates
- 7.94% for Direct Unsubsidized Loans to graduate or professional students
Federal law caps undergraduate rates at 8.25% and graduate rates at 9.5%.7Office of the Law Revision Counsel. 20 US Code 1087e – Terms and Conditions of Loans
Every disbursement also carries an origination fee of 1.057% for both loan types, deducted from the disbursement before it reaches your school.8Federal Student Aid. FY 26 Sequester-Required Changes to the Title IV Student Aid Programs On a $5,000 loan, roughly $53 is withheld, so you receive about $4,947, but you owe interest on the full $5,000.
Keeping the Interest Bill Down
The single most effective move with an unsubsidized loan is paying the interest as it accrues so it never capitalizes. Even modest monthly payments while you’re in school keep your balance from growing. On a $10,000 unsubsidized loan at 6.39%, that’s about $53 a month.
If a full interest payment isn’t realistic, pay what you can. Anything you cover reduces what eventually capitalizes. When you need a payment pause on subsidized loans, choose deferment over forbearance whenever you qualify, since the subsidy holds during deferment but not forbearance.1Federal Student Aid. Subsidized and Unsubsidized Loans
Active-duty servicemembers may qualify to have interest capped at 6% on eligible federal student loans during qualifying military service under the Servicemembers Civil Relief Act.9Federal Student Aid. Servicemembers Civil Relief Act (SCRA) Interest Rate Limitation Request For a graduate borrower sitting at 7.94%, that’s real savings; for a rate already below 6%, the cap does nothing.
One Way to Lose the Subsidy Early
Borrowers who first received a Direct Loan on or after July 1, 2013, can receive subsidized loans for no more than 150% of the published length of their program. A standard four-year bachelor’s degree gives you six years of subsidized eligibility.10Federal Student Aid. 150 Percent Direct Subsidized Loan Limit Information
If you reach that limit, you lose the interest subsidy on all your outstanding subsidized loans. From that point on, they accrue interest during in-school and grace periods just like unsubsidized loans do. Students who change majors or transfer and take longer to finish are the ones most often caught by this.