Capitalized interest on a student loan is unpaid interest that your lender adds to your principal balance, so from that point forward you are charged interest on a larger amount. It is the mechanism that makes a student loan grow while you are not paying it, and it is why a balance at graduation or after a forbearance can be noticeably higher than the amount you originally borrowed. Whether it happens to you, and how often, depends on your loan type and what you do during periods when payments are not required.
How Capitalization Works
Interest on a federal student loan accrues daily. Each day, your outstanding principal is multiplied by a daily rate, and that small amount is added to a running total of unpaid interest. On a standard repayment plan, your monthly payment absorbs all of that accrued interest and then some principal, so nothing builds up. When you are not paying — during school, a grace period, a deferment, or a forbearance — the interest keeps accumulating with nothing to offset it.1Federal Student Aid. Interest Rates and Fees for Federal Student Loans
Capitalization is the event where that pile of unpaid interest gets folded into your principal. After it happens, the daily interest calculation runs against the new, larger balance. You are now paying interest on prior interest.
A simple example: on a $10,000 loan at 6.39%, if $500 of unpaid interest capitalizes, your new principal is $10,500. Every future daily interest charge is calculated on $10,500 instead of $10,000. Over a ten-year payoff, that single event costs more than the $500 itself.
Subsidized vs. Unsubsidized: Whether Interest Builds at All
Before capitalization is even a concern, you need to know whether interest is accruing in the first place. With a Direct Subsidized Loan, you are not charged interest while enrolled at least half-time or during the six-month grace period after leaving school. The federal government covers that cost, so there is no unpaid interest to capitalize.2Federal Student Aid. Top 4 Questions: Direct Subsidized Loans vs. Direct Unsubsidized Loans
With a Direct Unsubsidized Loan, interest starts accruing the day the money is disbursed. Graduate PLUS and Parent PLUS loans work the same way. On any of these, every month you are not paying is a month that unpaid interest is building toward a possible capitalization event.2Federal Student Aid. Top 4 Questions: Direct Subsidized Loans vs. Direct Unsubsidized Loans
When Federal Loans Capitalize
Current rules limit the situations in which unpaid interest on a federal Direct Loan (and on Federal Family Education Loan Program loans held by the Department of Education) will capitalize. There are two triggers:
- At the end of a deferment on an unsubsidized loan, any interest that accrued during the deferment is added to principal.
- When you leave the Income-Based Repayment (IBR) plan or lose eligibility for income-based payments under that plan, unpaid interest capitalizes.
These are fewer triggers than existed under older rules.1Federal Student Aid. Interest Rates and Fees for Federal Student Loans The underlying regulation gives the Department authority to capitalize unpaid interest and specifically requires it at the end of a deferment on an unsubsidized loan.3eCFR. 34 CFR 685.202 – Charges for Which Direct Loan Program Borrowers Are Responsible
FFEL Program loans that are not held by the Department follow a broader set of rules. On those loans, interest can also capitalize after a forbearance and at the end of the grace period on an unsubsidized loan.1Federal Student Aid. Interest Rates and Fees for Federal Student Loans If you don’t know who holds your FFEL loan, your servicer can confirm it.
Two situations worth flagging. Most federal loans carry a six-month grace period after you graduate or drop below half-time. Interest on unsubsidized loans continues to accrue during that window, and on Department-held Direct Loans it doesn’t capitalize at the end of the grace period under the current rules — but it is still sitting there, and it will capitalize the next time a trigger occurs.4Federal Student Aid. How Long Is My Grace Period The other is deferment on an unsubsidized loan: the Department illustrates the cost with a $30,000 balance at 6% and a 12-month deferment, where letting the interest capitalize instead of paying it adds roughly $600 to the total repayment cost.5Federal Student Aid. In-School Deferment Request
Income-Driven Repayment
Under an income-driven repayment plan, your monthly payment is set by your income rather than your balance. If that payment doesn’t cover the full month’s interest, the shortfall sits as unpaid interest. Under current federal rules, that unpaid interest only capitalizes when you leave the IBR plan or lose eligibility for income-based payments there.6Federal Student Aid. IDR Plan Court Actions: Impact on Borrowers
When Private Loans Capitalize
Private student loans are governed by your promissory note, not federal regulations. The lender sets the capitalization schedule, and it can be as frequent as monthly. There is no federal ceiling on how often a private lender can capitalize interest.
Practically, that means two private loans with the same interest rate can produce very different totals depending on how often unpaid interest is folded into principal. Before you sign, check the disclosure for the capitalization schedule. Over several years of school and repayment, monthly capitalization on a private loan can add thousands of dollars compared with a loan that capitalizes only at defined events.
What Consolidation Does to Unpaid Interest
Consolidating federal loans into a Direct Consolidation Loan pays off the balances on your existing loans — including any accrued unpaid interest — and replaces them with one new loan. The interest that had been sitting on the old loans becomes part of the new principal.7Federal Student Aid. Chapter 6 Loan Consolidation in Detail It is a one-time, permanent capitalization event that is easy to miss because it is bundled into the paperwork.
If you are considering consolidation and have a meaningful amount of unpaid interest already sitting on your loans, paying that down first will lower the principal you carry into the new loan.
How to Prevent Capitalization
The most direct way to prevent capitalization is to prevent unpaid interest from accumulating in the first place. Federal servicers accept voluntary payments during school, grace periods, and deferment. Even $20 or $30 a month toward interest on an unsubsidized loan keeps the balance from growing.5Federal Student Aid. In-School Deferment Request
A few other habits help:
- Know which of your loans are subsidized and which are unsubsidized, so you can direct any voluntary payments to the loans that are actually accruing interest.
- Avoid deferment or forbearance on unsubsidized loans if you can afford any payment. Staying in active repayment is usually cheaper over the life of the loan.
- Recertify your income on time if you are in an income-driven plan. Missing the deadline can move you off the plan and trigger capitalization.
- On a standard, graduated, or extended repayment plan, the monthly payment covers all accruing interest, so nothing builds up to capitalize.1Federal Student Aid. Interest Rates and Fees for Federal Student Loans
Tax Treatment When You Pay It Back
Once unpaid interest has been capitalized, the IRS still treats it as interest when you eventually pay it down. As you repay the loan, the portion of each payment attributable to the capitalized amount counts toward the student loan interest deduction. No deduction is available in a year in which you make no payments.8Internal Revenue Service. Publication 970, Tax Benefits for Education
The maximum deduction is $2,500 per year. It phases out between $85,000 and $100,000 of modified adjusted gross income for single filers, and between $175,000 and $205,000 for joint filers. You claim it as an adjustment to income, so you don’t have to itemize to take it.