Student Loan Interest Capitalization: How Unpaid Interest Grows Your Balance
October 21, 2026
On an unsubsidized student loan, interest accrues from the day the money is disbursed, even while you are in school. A $30,000 loan at 6.5% accrues about $30,000 × 0.065 × 4 = $7,800 of interest over four years. If that interest is capitalized, meaning added to the principal, you begin repayment owing about $37,800 and pay interest on the larger amount.
Skip the math and get your answer instantly:
Open the Loan Calculator →Accrual vs. Capitalization
Accrual is the daily build-up of interest. Capitalization is the moment the unpaid interest is added to your principal balance. After capitalization, future interest is calculated on the new, higher balance, which is what makes the loan grow faster.
In the example, annual interest at the start of repayment would be 6.5% of $37,800 = $2,457, compared with $1,950 on the original $30,000, an extra $507 per year in interest.
The Cost of Letting Interest Build
Compare repayment of $30,000 against $37,800 over 10 years at 6.5%. The monthly payment is about $340.64 on the original balance and about $429.21 on the larger one. That is an extra $88.57 per month, or about $10,600 over 10 years, for the interest that built up in school.
Capitalization events vary by loan type and servicing rules, and have changed over time, so verify current policy with your servicer.
| Balance at repayment | Monthly payment (10 years, 6.5%) | Total paid |
|---|---|---|
| $30,000 (interest paid during school) | $340.64 | $40,877 |
| $37,800 (interest capitalized) | $429.21 | $51,505 |
How to Limit the Growth
If you can, pay the interest while in school, even $50 to $100 a month, which keeps the balance from growing. Any payment above that reduces principal. If you have a grace period, consider paying interest during it so it does not capitalize when repayment begins.
After graduation, try to pay more than the minimum on the highest-rate loans first, and check whether refinancing makes sense, keeping in mind that refinancing federal loans into private loans removes federal protections.
Frequently Asked Questions
Do unsubsidized loans accrue interest while I'm in school?
Yes. Interest accrues from disbursement, and unpaid interest may be capitalized later.
What is capitalization?
Adding unpaid interest to your loan principal so that future interest accrues on the larger balance.
Is it worth paying interest while in school?
Usually yes if you can afford it, because it prevents your balance from growing.
Do subsidized loans accrue interest in school?
Generally no. The government pays interest during school and certain deferment periods.