When Your Student Loan Minimum Does Not Cover the Interest

This loan does not have a long payoff time. It has none

Most calculators will answer this question with a number, and the number will be a lie. At 8% on a $96,000 balance, the interest that accrues in a month is larger than the $600 the servicer bills you. Paying exactly what you were asked to pay therefore does not reduce the balance by a little; it does not reduce it at all. It increases it, every month, for as long as the arrangement holds. A tool that responds to this with a payoff date is reporting its own iteration limit dressed up as arithmetic, which is why this page reports it as a distinct outcome and shows you the balance a year from now instead. That growing figure is the one honest number available here.

The number you actually need is not a payoff date, and it is easy to work out yourself: the monthly interest is the balance multiplied by the annual rate and divided by twelve. Any payment above that figure starts reducing principal; any payment below it does not, however long you keep making it. Getting above that line by even a small margin changes the situation from a category to a quantity — the loan goes from having no ending to having one, and every dollar past the line then does ordinary work. That is why the extra payment field matters more on this page than anywhere else on the site. The $250 modelled above is not a nicety here; it is what turns the question into one that has an answer at all, and the second column shows what that answer becomes.

Being in this position is more common than it sounds and it is not always a mistake. Some repayment arrangements deliberately set a payment below the accruing interest for a period, on the understanding that the shortfall is subsidised or added to the balance later. Growing balances also show up during graduated repayment, during forbearance, and whenever someone is paying a token amount while income recovers. What makes it dangerous is capitalization: when unpaid interest is added to principal at the end of such a period, the interest starts earning interest and the loan you owe becomes larger than the loan you borrowed. This calculator does not model any capitalization event. It treats the balance you entered as today's balance and never rolls unpaid interest into it, which means the real trajectory of an unaddressed shortfall can be worse than what is shown.

So the first action is not arithmetic, it is a phone call. Ask your servicer which repayment arrangement you are currently on, whether the payment is meant to cover the interest, and whether unpaid interest will be capitalized and when. If any part of the balance is a US federal loan, ask specifically what income-linked arrangements you qualify for, because a payment tied to your earnings is the mechanism designed for exactly this situation — and note that refinancing privately would end access to it permanently.

Finding the payment that turns this into a question with an answer

Treat this page as a search for a threshold rather than a request for a payoff date. Raise the extra payment field from zero in small steps and watch the second column: for a while it will report the same non-answer as the first, and then at some point it flips and begins reporting a schedule that finishes. That flip is not gradual. It is the moment the total payment crosses the monthly interest on a $96,000 balance at 8%, and it is the single most useful thing this page can tell you.

Once you are past it, the ordinary rules apply again and they apply with unusual force. Just above the line almost the whole payment is still interest, so the first hundred dollars past the threshold buy far more than the next hundred. This is the steepest part of the curve that exists anywhere in consumer lending, and it is why an amount that looks too small to matter here is not too small to matter.

Two other levers change the threshold itself rather than your position relative to it. Lowering the rate lowers the interest accruing each month, which is why the refinance column can show a finishing schedule even where the current minimum shows none — and why, for a federal balance, that particular escape is bought at the permanent cost of the protections a growing balance is most likely to need. Lowering the balance does the same thing arithmetically, which is what a lump sum against principal accomplishes.

What no lever on this page can do is fix a payment that is structurally unaffordable. If the threshold payment is beyond your income rather than merely uncomfortable, the answer is an arrangement that ties the payment to earnings, not a different number typed into a calculator. Ask your servicer what you qualify for before the unpaid interest is capitalized.

When the minimum payment never gets you anywhere

If your minimum payment is at or below the interest accruing each month, the loan does not have a long payoff time. It has none. The balance grows every month you pay exactly as agreed, and it will keep growing for as long as that arrangement holds. This page reports that as its own outcome rather than as a very large number of months, because a month count in that situation is not an answer — it is whatever the calculator's iteration limit happened to be, dressed up as arithmetic. When you see it, the number you need is not a payoff date but the payment that would start reducing the balance at all, which is anything above the monthly interest: the balance multiplied by the annual rate, divided by twelve.

This situation is more common than it sounds, and it is not always a mistake. Some repayment arrangements deliberately set a payment below the accruing interest for a period, on the understanding that the shortfall is either subsidised or added to the balance later. Growing balances also show up during a graduated repayment period, during forbearance, and whenever a borrower is paying a fixed token amount while income recovers. What makes it dangerous is unpaid interest being capitalized — added to principal — at the end of such a period, because from that moment the interest starts earning interest, and the loan you owe is larger than the loan you borrowed. This calculator does not model any capitalization event; it assumes the balance you enter is the balance today and that no unpaid interest is ever rolled into it.

A second thing this calculator will not do is invent a payoff date for a schedule that technically amortizes but takes longer than a century. A payment one dollar above the monthly interest does eventually clear the loan, in the same sense that a dripping tap eventually fills a reservoir. Reporting that as a number of years would be technically true and practically worthless, so it is reported as its own outcome too. Between them, these two rules mean every figure this page shows you comes from a schedule that actually finishes.

A lower monthly payment is not a cheaper loan

The most common way a refinance quote misleads has nothing to do with the rate. It is the term. Stretching the same balance over more years lowers the monthly payment arithmetically, whatever happens to the rate, and a quote that leads with the new monthly figure is inviting you to read a longer term as a discount. It is not one: you pay interest for every year the loan exists, so more years at a lower rate can easily cost more in total than fewer years at a higher one. This page flags that case explicitly rather than letting the monthly figure carry the argument, and the interest row will show a negative saving when it happens.

That does not make a longer term wrong. A lower required payment has real value if it is the difference between meeting your obligations comfortably and living one bad month away from a missed payment, and buying that breathing room with additional interest can be an entirely rational purchase. The point is to know the price. Refinancing to a longer term and then voluntarily paying the old, higher amount each month gets you both the lower obligation and the shorter payoff, which is often the best available structure — run that case here by entering the refinance and putting the difference in the extra payment field.

Two things this calculator does not include are worth naming. It applies no origination or application fee to the refinance, so a quote that carries one is slightly better on this page than in life; add any such fee to the balance before comparing if you want the honest figure. And it assumes a fixed rate throughout. A variable-rate refinance offer will usually quote a starting rate below any fixed alternative, and that rate is not a promise — modelling it as fixed here would understate its cost in any environment where rates rise. If the offer in front of you is variable, run this page at the highest rate the contract permits, not the one on the marketing page, and see whether the comparison still favours it.