Debt & Loans
Student Loan Payoff Calculator
Your balance on the standard 10-year plan — and what an extra $100 a month does to the date and the interest.
One loan, one fixed rate, standard amortization — no income-driven plans or forgiveness modeled. Dates count from July 2026.
How it works
The standard federal repayment plan is a plain fixed loan: level payments sized so the balance hits zero in 10 years. Each month, one-twelfth of the rate lands on the remaining balance as interest, and your payment covers that plus a slice of principal. The default balance of $38,000 is roughly what the average US borrower owes, and at 6.5% — the recent neighborhood for federal undergraduate rates — the standard plan works out to $431 a month, $13,778 in total interest, and a final payment in Jul 2036.
That interest number is the one worth sitting with: on the standard schedule, a $38,000 education quietly costs about $51,800. The orange curve shows why — in the early years most of each payment is interest, so the balance barely moves, then the curve steepens as principal takes over.
The + $100/mo chip is the point of this page. Tap it and a dashed green line replays your payoff with $100 more each month, every extra dollar going at principal. The note under the chip prints exactly how many months sooner you're done and how much interest you keep — computed from your numbers, not a slogan. For most balances the answer is years and thousands, which is a lot of leverage for one streaming-tier-sized decision a month.
The formula
payment = balance × r / (1 − (1 + r)^−n) r = rate/1200 · n = years × 12 total interest = payment × n − balance Example: $38,000 at 6.5% for 10 years → $431/mo · $13,778 interest · done Jul 2036 + $100/mo: same loan replayed at $531/mo, month by month, until the balance hits $0
Honest assumptions
- One loan, one fixed rate. Real borrowers usually hold several loans at different rates — your true picture is the sum of them, and the payoff order across them matters.
- Standard amortized repayment only — no income-driven plans, forgiveness programs, subsidies, deferment, or forbearance are modeled. Those change the math completely, and this page doesn't pretend otherwise.
- 6.50% is an example in the recent federal undergraduate neighborhood, not an offer and not your rate — federal rates are set per loan per year, and private rates vary by lender and credit.
- No tax modeling — the student-loan interest deduction some borrowers can take isn't included.
- This page is arithmetic, not underwriting.
Questions people ask
Why does this model the standard plan and not income-driven repayment?
Because the standard plan is the fixed benchmark every other option is measured against, and it's the only one a calculator can compute honestly from a balance and a rate. Income-driven plans set your payment from income and family size under rules that have changed repeatedly, and some end in forgiveness — modeling that here would mean guessing at your paycheck and at future policy. If you're weighing IDR, the federal loan simulator at studentaid.gov runs those rules with your actual data; this page tells you what the debt costs when you simply pay it down.
I have several loans — which one gets the extra $100?
Mathematically, the highest-rate loan, while paying minimums on the rest — the avalanche order, which minimizes total interest across the whole stack. Paying the smallest balance first (the snowball) costs somewhat more but retires whole loans faster, which keeps some people going. This page simulates one loan at a time; run each of yours through it, or use the debt payoff calculator to see what an extra amount does to any single balance.
Does an extra payment actually go to the principal?
Not always by default — some servicers treat extra money as "paying ahead" and just advance your due date, which does far less for you. Tell your servicer explicitly to apply extra payments to principal (most have a setting or a memo line for it), and check the next statement to confirm the balance dropped by the full extra amount. The green line on this page assumes principal application — make your servicer match the assumption.
Should I refinance to a lower rate?
A lower rate genuinely shrinks the interest total — you can see exactly how much by typing the quoted rate into the field above. But refinancing federal loans with a private lender permanently gives up federal protections: income-driven plans, potential forgiveness, generous deferment and forbearance. That trade can be fine or terrible depending on how secure your income is, and no calculator can weigh that for you. This page shows the arithmetic side only; it is not a recommendation either way.
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