What Your Loan Really Costs
This calculator shows the total amount you will pay over the life of your student loan, not just the principal you borrowed. Enter your balance, rate, and term. On a $180,000 loan at 6.5% over 10 years, total payments exceed $245,000 — more than $65,000 in interest alone. The tool shows how each payment splits between interest and principal.
What you hand over in total
To borrow — that is of interest, or of interest for every dollar you borrowed.
- Monthly payment
- Interest in year one
- Share of year one that is interest
- Interest over the term
- Total paid by
Of your very first payment, is interest and only touches the balance. That flips slowly, month by month.
Fixed rate, no missed payments, nothing extra. Interest is accruing at a day on the balance you entered.
Monthly payment
Total interest
Interest vs principal
Debt-free
Year by year
| Year | Opening | Interest | Principal | Closing |
|---|
Swipe the table sideways to see every column.
Where Your Money Goes in Year One
In the first year of a $180,000 loan at 6.5%, roughly $11,600 of your payments goes to interest and only about $12,500 goes to principal (illustrative, based on a 10-year standard repayment). That split means nearly half of every dollar you send to your servicer in year one does not reduce your balance. By year five the ratio shifts: interest drops as the principal shrinks, and more of each payment chips away at the debt itself.
This front-loading of interest is standard amortization, not a lender trick, but it surprises borrowers who assume steady progress from day one. The calculator displays the interest-to-principal split for every year of the term so you can see the curve flatten. Understanding this pattern explains why extra payments early in the loan—when the balance and daily interest charge are highest—produce larger lifetime savings than the same extra payment made in year eight. The payoff calculator shows how adjusting your payment moves the debt-free date.
Total Cost Beyond the Sticker Rate
Your interest rate is a per-year charge, but the total cost of the loan depends on how long that rate compounds. A $180,000 balance at 6.5% over 10 years costs roughly $65,000 in interest. Extend the same loan to 20 years—common in income-driven repayment—and total interest can exceed $130,000, even if the rate stays the same. The rate did not change; the time did.
This is why comparing loan options on rate alone is incomplete. A lower-rate refinance that extends your term may reduce your monthly payment while increasing your total cost. The calculator lets you test multiple term lengths on the same balance and rate so you can see that trade-off in dollars. If your employer offers the $5,250 annual tax-free student-loan repayment benefit—made permanent under OBBBA and inflation-indexed from 2027—factor that contribution as additional principal reduction. Even a partial employer match shifts the amortization curve meaningfully on a high-balance loan.
All examples use standard amortization with a fixed rate. Actual total cost varies by repayment plan, rate type, and any extra payments made.
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Sources
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Sources: standard amortization formula (daily interest = principal x APR / 365.25); mercer.com OBBBA §70412 employer repayment benefit (permanent, inflation-indexed from 2027).
- Federal Direct Consolidation Loan interest rate — the weighted average of the loans being consolidated, rounded up to the nearest one-eighth of one percent (Federal Student Aid, studentaid.gov, Loan Consolidation).
- Amortisation, daily interest accrual and payoff arithmetic — standard loan mathematics; every figure on this page is computed from the numbers you enter.