Yes, most student loans charge interest, and it starts accruing immediately
Interest is a percentage of the money you borrow that you pay back on top of the original amount. Nearly all student loans — federal and private — charge interest. The only exception is subsidized federal loans, where the government pays the interest while you are in school at least half-time. Once you leave school or drop below half-time enrollment, interest starts accruing on those too.
How much interest you pay depends on the loan type, the interest rate, and how long you take to repay. A federal loan at 5% interest costs far less over time than a private loan at 10%. The difference between the two can amount to thousands of dollars on a $30,000 loan.
Interest can be simple (calculated only on what you originally borrowed) or compound (calculated on what you owe plus accumulated interest). Most student loans use simple interest while you are in school or in deferment, but compound interest applies once you enter repayment.
Key Takeaways
- Subsidized federal loans do not accrue interest while you are enrolled at least half-time, but unsubsidized loans and private loans do.
- Federal student loan interest rates are set by Congress and change each year; private loan rates depend on your credit and the lender.
- Interest that accrues while you are in school can be capitalized (added to your principal) when repayment begins, increasing what you owe.
- The total interest you pay over the life of the loan depends on the interest rate, the repayment plan you choose, and how long you take to repay.
Federal loan interest rates and how they are set
Federal student loan interest rates are determined by Congress, not by the Department of Education or your school. Congress sets a new rate each year, usually in May, and that rate applies to all loans issued during that fiscal year (which runs October through September). The rate stays the same for the life of that loan — it does not change year to year once you have borrowed.
As of 2024, federal undergraduate loans carry a fixed rate set by Congress; graduate loans and Parent PLUS loans have their own separate rates, also set by Congress. You can find the current rates on the Federal Student Aid website, which updates them each year. Rates have ranged from around 4% to over 8% in recent years, depending on what Congress set.
Because federal rates are fixed, you know exactly what you will pay in interest before you borrow. This is different from private loans, where the rate can vary based on your credit score, income, and the lender's policies.
Private loan interest rates and how lenders decide them
Private student loan lenders set their own interest rates based on your creditworthiness. A lender will look at your credit score, income, debt-to-income ratio, and sometimes your school and major. A borrower with excellent credit might receive a rate of 4%, while someone with fair credit might be offered 10% or higher from the same lender.
Private loans can have fixed rates (the same for the life of the loan) or variable rates (which change based on market conditions, usually annually). Variable-rate loans start lower but can increase significantly over time. If you take a variable-rate private loan at 5% and rates rise, your payment could jump to 8% or 9% in future years.
Private lenders also do not have to offer the same protections as federal loans — no income-driven repayment plans, no forgiveness programs, and no automatic deferment if you lose your job. The interest rate is often the least important factor when comparing private loans to federal loans.
How interest accrues while you are in school
Unsubsidized federal loans and all private loans begin accruing interest the day they are disbursed, even if you have not started repayment yet. That interest sits there, unpaid, while you are in school. When you graduate or leave school, that accumulated interest is usually capitalized — added to your principal balance — so you end up owing more than you originally borrowed.
For example, if you borrow $10,000 in an unsubsidized loan at 5% interest and it accrues for four years while you are in school, roughly $2,200 in interest will be added to your balance. You will then repay $12,200, not $10,000. That extra $2,200 will itself accrue interest during repayment, making the total cost even higher.
Subsidized federal loans do not accrue interest while you are enrolled at least half-time. The government covers the interest during school and during certain deferment periods (like economic hardship deferment). This is why subsidized loans are generally better than unsubsidized loans if you can get them — you borrow less total money.
Interest capitalization and how it increases what you owe
Capitalization is when unpaid interest is added to your principal balance. Once interest is capitalized, you pay interest on that interest during repayment. This happens automatically on most loans when you leave school or when you exit forbearance or deferment.
Capitalization can happen multiple times. If you use income-driven repayment and your payment does not cover the full interest owed each month, the unpaid interest capitalizes annually. This means your balance grows even though you are making payments. Over a 20-year income-driven repayment plan, capitalization can nearly double what you owe.
You can prevent some capitalization by paying interest while you are in school, even small amounts. If you pay $50 per month toward interest while in school, that $50 will not be capitalized later. This is optional but can save you thousands over the life of the loan.
How repayment plan choice affects total interest paid
The repayment plan you choose determines how much interest you pay overall. A standard 10-year repayment plan has a higher monthly payment but costs less in total interest. An income-driven plan (like PAYE or SAVE) has a lower monthly payment but extends repayment to 20 or 25 years, meaning you pay far more interest.
On a $30,000 federal loan at 5% interest, a 10-year standard plan costs roughly $7,900 in total interest. The same loan on a 25-year income-driven plan costs roughly $20,000 in total interest — more than double. However, income-driven plans also offer forgiveness: any balance remaining after 20 or 25 years is forgiven (though you may owe taxes on the forgiven amount).
The "best" plan depends on your income and goals. If you can afford the standard payment, you pay less interest. If you cannot, an income-driven plan keeps your payment manageable but costs more in interest over time.
What happens if you do not pay interest while repaying
If your monthly payment does not cover the full interest owed, the unpaid interest capitalizes. This is common on income-driven repayment plans, where payments are based on income rather than what the loan actually costs to service.
For example, on the SAVE plan, if your income is very low, your payment might be $0. Interest still accrues, and if you make no payment, that interest capitalizes after a year. Your balance grows even though you are enrolled in the plan. This is not a penalty — it is how the math works — but it means you owe more at the end than you borrowed at the start.
Some borrowers choose to make interest-only payments while in school or during low-income periods to prevent capitalization. Others accept capitalization as part of the trade-off for a lower monthly payment now.
Frequently Asked Questions
Can I pay off interest before it capitalizes?
Yes. You can pay interest at any time, even while in school or in deferment. Paying interest before capitalization prevents it from being added to your principal, which saves you money over the life of the loan. There is no penalty for paying interest early on federal loans.
Do federal and private loans charge interest differently?
Federal loans have fixed rates set by Congress each year. Private loans have rates set by the lender based on your credit. Federal rates are the same for all borrowers in a given year; private rates vary by borrower. Federal loans also offer protections like income-driven repayment; private loans do not.
What is the difference between fixed and variable interest rates?
A fixed rate stays the same for the entire life of the loan. A variable rate changes, usually annually, based on market conditions. Fixed rates are predictable; variable rates start lower but can increase significantly. Most federal loans have fixed rates. Some private loans offer variable rates.
Will my interest rate change after I graduate?
No. Federal loan interest rates are fixed for the life of the loan — they do not change after graduation. Private loan rates depend on whether you chose a fixed or variable rate when you borrowed. If you chose fixed, it stays the same. If you chose variable, it can change annually.
How much total interest will I pay on my student loans?
Total interest depends on the loan amount, interest rate, and repayment plan. A $30,000 loan at 5% costs roughly $7,900 in interest on a 10-year plan or $20,000 on a 25-year plan. Use the federal loan calculator on StudentAid.gov to estimate your specific loan's total cost based on your repayment plan.