What Is Student Loan Interest?

Written by: Therese (she/her)

2 min read | Published: September 17, 2026

A person reviews paperwork at a desk with a notebook and laptop

If you’re thinking about taking out student loans, you may already have an idea of how much you’re borrowing. However, there’s another important piece of the puzzle that’s easy to overlook: interest.

Student loan interest is the fee assessed and paid to your student loan lender. It’s the cost of borrowing money for your education, and it’s based on your unpaid student loan balance, the number of days since a payment was made and your interest rate. While your interest rate may seem like just another number on your loan paperwork, understanding how interest works can help you make more informed borrowing decisions and better prepare for repayment after graduation.

Why Interest Matters

When you take out a student loan, you’ll repay the amount you borrowed, known as the principal, plus interest. The more interest that accrues over time, the more you’ll repay overall. According to the Federal Student Aid office, interest rates are determined by the type of federal loan you receive and are set by Congress each year.

Understanding how interest works can help you see why borrowing only what you need is so important. While it may be tempting to accept the full loan amount you’re offered, every dollar you borrow has the potential to increase the total amount you’ll repay over time. The U.S. Department of Education encourages students to understand the terms of their loans before accepting financial aid. Before accepting a loan, take time to understand the amount you’re borrowing, your interest rate and your repayment responsibilities, so you know what to expect after graduation.

Not All Student Loans Work the Same

One of the biggest misconceptions about student loans is that they all work the same way. In reality, different loan types have different rules when it comes to interest. For example, the Federal Student Aid office explains that Direct Subsidized Loans generally don’t accrue interest while you’re enrolled in school at least half-time or during your six-month grace period after graduation. Direct Unsubsidized Loans, however, begin accruing interest as soon as the loan is disbursed. Their shared characteristic is that all direct loans are assessed with daily interest. This means that while the point at which interest starts accruing may differ between subsidized and unsubsidized loans, the interest is assessed daily once it starts. Meanwhile, private student loans can have different terms, interest rates and repayment requirements depending on the lender.

If your budget allows, making interest payments on loans that accrue interest while you’re still in school may help reduce the amount that’s added to your loan balance before repayment begins. Even small payments can make a difference over time. It may also be helpful to know your loan servicer and understand your repayment options before your first payment is due. The Federal Student Aid office provides tools to help borrowers manage their loans throughout repayment.

Building Good Borrowing Habits

Student loans help millions of students pursue higher education each year, and borrowing money for school isn’t necessarily a bad thing. The key is understanding the terms of your loans before you sign, knowing when interest begins to accrue, and having a plan for repayment after graduation. Taking a little time to understand how student loan interest works today can help you make more confident financial decisions tomorrow.