See exactly how much your student loan balance grows when unpaid interest capitalizes — and what that costs you over the life of the loan.
Interest doesn't stop building just because you're not making payments — during deferment, forbearance, an in-school period, or a grace period, your unsubsidized (or subsidized-but-no-longer-covered) loans keep accruing interest every day. That accrued interest sits separately from your principal until a trigger event causes it to capitalize — get folded into your principal balance. From that point forward, you pay interest on the interest, not just on what you originally borrowed. This calculator shows you the size of that jump and its long-term cost, based on the standard simple daily interest formula federal loan servicers use.
Interest accrued during your pause is calculated as: Balance × (Annual Rate ÷ 12) × Number of Months. That amount, plus any interest that was already sitting unpaid, gets added to your principal the moment it capitalizes. Your new, larger balance is then what gets amortized over your remaining repayment term — which is why the increase in your monthly payment is usually bigger than the capitalized amount alone would suggest: you're now paying interest on a permanently higher principal for the rest of the loan.
Example: a $30,000 balance at 6.52% paused for 12 months accrues about $1,956 in interest. If that capitalizes, your new balance is $31,956 — a 6.5% jump in principal that also raises your monthly payment and adds well over $1,956 to your total lifetime cost, because the extra principal itself now earns interest for the rest of the term.
Capitalization is event-driven, not automatic on a schedule. The most common triggers historically have been: the end of a deferment or forbearance period, the end of your grace period after leaving school, switching out of certain income-driven repayment plans, finalizing a loan consolidation, and exiting default. A 2023 federal rule change removed capitalization from several of these triggers going forward — and rules have continued to shift since, most recently with the 2026 transition away from the SAVE plan. Because the list of active triggers has changed more than once in a short period, always confirm your loan's current status at studentaid.gov or with your servicer rather than assuming an older rule still applies.
The most reliable way to avoid capitalization is to pay off accrued interest before the trigger event happens — for example, making interest-only payments during a deferment, or paying the unpaid interest balance in full right before a plan switch or consolidation finalizes. Even a partial payment toward the accrued interest reduces how much ends up capitalizing. If you're choosing between forbearance and an income-driven plan with a $0 or low payment, the income-driven option is often better specifically because it may avoid a capitalization trigger that forbearance does not — run both scenarios through this calculator with your actual numbers before deciding.
Can I avoid capitalization entirely? Yes. If you pay the accrued interest before the capitalization trigger (end of deferment, forbearance, or grace period, or before you finalize a plan switch or consolidation), that interest never gets added to your principal — you pay it once, at its original amount, instead of paying interest on it for the rest of your loan term. Even paying a partial amount reduces how much capitalizes.
Does capitalized interest ever get reversed? It has happened before as a one-time relief measure (for example, a 2023 rule change removed capitalization from several federal triggers going forward), but reversing interest that has already capitalized is rare and not something to plan around. Treat any capitalized interest as a permanent part of your principal unless your servicer or studentaid.gov specifically announces otherwise.
Does capitalization happen automatically every month? No — interest accrues daily, but it only capitalizes at specific trigger events: the end of a deferment, forbearance, or grace period, switching out of certain repayment plans, finalizing a loan consolidation, or exiting default. Federal rules on which triggers apply have changed more than once in recent years, so confirm your loan's current status at studentaid.gov before assuming a specific trigger applies to you.
Do private student loans capitalize the same way? The concept is the same — unpaid interest gets added to principal — but private lenders set their own triggers and some capitalize more frequently than federal loans, including monthly in certain cases. Check your promissory note or ask your servicer directly, since private loan terms vary widely by lender.
Does interest capitalization hurt my credit score? Capitalization itself is not reported to credit bureaus and does not directly affect your score — only missed or late payments do that. The indirect risk is a higher monthly payment after capitalization, which can raise your debt-to-income ratio and make it harder to qualify for other credit like a mortgage.
Student Loan Calculator — full monthly payment and total cost breakdown.
Loan Repayment Calculator — compare Standard, IBR, and RAP plans side by side.
How to Lower Your Student Loan Interest Rate — refinancing and rate-reduction strategies.
How to Lower Your Student Loan Payments — options if your current payment isn't manageable.