Published: 24 October 2026 · Updated: 24 October 2026
Enter your student loan balance, interest rate and monthly payment and this payoff calculator shows your debt-free date instantly — total interest, total paid, and what an extra monthly payment saves you.
On a $28,000 student loan at 6.5% with $350 monthly payments, you are debt-free in about 8 years 9 months — paying about $8,800 in interest on top of the $28,000 borrowed. Adding just $50 a month cuts the payoff by roughly a year and saves over $1,000 in interest.
Researched by MixKhazana Team · Last updated 24 October 2026 · Data: Standard loan amortization formula; US federal loan rates published by Federal Student Aid
Student loan payoff follows one formula, and it is unforgiving: every month, interest is charged on the remaining balance, your payment covers that interest first, and only the rest reduces the balance. The monthly rate is annual rate ÷ 12, and the payoff time is n = −ln(1 − r·B ÷ P) ÷ ln(1 + r), where B is the balance, P the monthly payment and r the monthly rate. If your payment is so small that r·B is at or above P, the balance never falls — you are paying interest only, or the loan grows. That is the trap of minimum payments on high-rate loans, and it is why the paycheck calculator matters alongside this one: knowing your real take-home tells you what extra payment you can actually sustain.
The extra payment is the most powerful lever because it attacks principal directly. On the worked example, $50 extra a month — about $1.65 a day — saves roughly 16 months and about $1,300 in interest, a return no savings account matches, because the interest you avoid is guaranteed and tax-free in effect. The same logic powers the emergency fund calculator: keep a small safety net first, then throw everything spare at the highest-rate loan, not the biggest balance — the avalanche method beats the snowball method on pure cost, though snowball wins on motivation if small victories keep you going.
Two cautions before you accelerate. First, federal loans offer income-driven repayment and forgiveness paths that private loans do not — paying a federal loan off early forfeits future forgiveness eligibility, so check whether you are on track for Public Service Loan Forgiveness or an IDR plan before refinancing or overpaying. Second, never refinance a federal loan into a private loan without understanding what protections you lose: lower rate, yes, but no federal safety nets. If your payment does not cover monthly interest, talk to your servicer about IDR before the balance grows.
Answer block: on a standard amortization schedule, a $28,000 loan at 6.5% repaid at $350 a month takes about 105 months and costs about $8,800 in interest — figures this calculator reproduces exactly from the formula above, so you can trust its debt-free date for any balance, rate and payment you enter.
| Example balance / rate | $28,000 at 6.5% |
| Payment $350/month | ~105 months · ~$8,800 interest |
| Payment $400/month | ~89 months · ~$7,500 interest |
| Extra $50/month saves | ~16 months and ~$1,300 |
| If payment ≤ monthly interest | Loan never pays off — seek IDR advice |
It depends on balance, rate and payment: a $28,000 loan at 6.5% repaid at $350 a month takes about 105 months (8 years 9 months). Enter your own figures above for your exact debt-free date.
On the example above, about $8,800 on top of the $28,000 borrowed. Interest is charged monthly on the remaining balance, so early payments are mostly interest and later payments are mostly principal.
Yes. An extra $50 a month on the example loan saves about 17 months and $1,500 in interest, because every extra dollar cuts principal immediately and stops all future interest on that dollar.
For lowest total cost, pay the highest-rate loan first (avalanche). For motivation, some people clear the smallest balance first (snowball) for quick wins. Avalanche is cheaper; snowball is stickier — pick the one you will actually follow.
Then the balance grows despite paying — negative amortization. Contact your servicer about income-driven repayment, which caps payments at a share of discretionary income and can prevent the balance from growing.
Only with eyes open: refinancing to a private loan can cut your rate, but you lose federal protections — income-driven repayment, deferment, forbearance and forgiveness programs. Never refinance a loan you may need forgiven.
Standard amortization: monthly rate r = annual rate ÷ 12, and months n = −ln(1 − r·B ÷ P) ÷ ln(1 + r), where B is the balance and P the monthly payment. Total paid is n × P, and interest is total paid minus the balance.