Student Loan Refinance Calculator

Enter your current balance, rate, and monthly payment, then the refinance offer's rate and term. You'll see the new payment, both payoff timelines, total interest on each path, and what refinancing saves (or costs) over the life of the loan.

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How this comparison works

First it figures out where your current loan is headed: given your balance, rate, and the payment you actually make, it simulates month by month until the balance hits zero, counting every dollar of interest along the way. Then it prices the refinance — a fresh loan at the new rate and term — and puts the two side by side: monthly payment, payoff date, total interest, and the lifetime difference. Watch that last row closely: a lower monthly payment with a longer term can quietly cost you more in total interest, and the calculator will say so.

The formula

M = B × r / (1 − (1 + r)−n)

M is the new monthly payment, B your balance, r the monthly rate (annual ÷ 12), and n the number of months in the new term. Your current path doesn't need a formula — it's simulated directly from the payment you're making, which also catches the nasty case where your payment doesn't even cover monthly interest and the balance grows instead of shrinking.

Worked example

$40,000 at 7%, currently paying $500/month, refinanced to 5% over 10 years:

Staying put pays the loan off in 9 years, 1 month with $14,037.84 of interest. The refinance drops the payment to $424.26 — saving $75.74/month — and total interest falls to $10,911.45, for lifetime savings of about $3,126. Want savings instead of breathing room? The same balance at 4% over just 5 years costs $736.66/month but saves about $9,838 in total. Rate cuts save you money; term cuts save you more.

The federal loan warning — read this before refinancing

Refinancing is done by private lenders. The moment you refinance a federal student loan, it becomes a private loan, and that conversion is permanent — you cannot change your mind later. You give up income-driven repayment plans (payments tied to what you earn), Public Service Loan Forgiveness (PSLF) and other federal forgiveness programs, and federal deferment and forbearance protections that let you pause payments through unemployment or hardship. If you work in public service, expect to use an income-driven plan, or have shaky income, a lower rate is usually a bad trade for that safety net. Refinancing shines for private loans (nothing to lose), and for federal borrowers with high rates, stable income, and no forgiveness path — decide with your eyes open.

Frequently asked questions

Should I refinance my federal student loans?

Only with great caution. Refinancing converts federal loans to private ones permanently, forfeiting income-driven repayment, Public Service Loan Forgiveness, and federal deferment and forbearance protections. It tends to make sense only if you have a high rate, very stable income, and no path to forgiveness — private loans, by contrast, have none of these protections to lose.

When does refinancing a student loan make sense?

When the new rate is meaningfully lower (a percentage point or more), your credit and income have improved since you borrowed, and you don't need federal protections. Compare total interest, not just the monthly payment — a lower payment stretched over more years can cost more overall.

Why is my total interest higher even though my payment dropped?

Term stretching. If you're on pace to pay off in 6 years and refinance into a 10-year loan, you're paying interest for 4 extra years — sometimes more than the lower rate saves. This calculator's lifetime savings row flags exactly this case and shows the true cost either way.

What credit score do I need to refinance student loans?

Most lenders want a score in the high 600s at minimum, with the best advertised rates reserved for the mid-700s and up, alongside a stable income and reasonable debt-to-income ratio. A creditworthy cosigner can bridge the gap, but remember they're then fully on the hook too.

What if my current payment barely covers the interest?

If your payment is less than or equal to the monthly interest accrued, the balance never shrinks — the calculator detects this and warns you. In that situation refinancing into any fixed term at least guarantees a payoff date, though the required payment may be higher than what you're paying now.

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