A student loan refinance calculator compares an existing loan's balance, rate, and remaining term with a proposed rate, term, and refinance fee. It estimates payment changes, interest differences, and total modeled cost under those inputs.
Refinancing replaces the existing loan with a new loan. A lower rate or payment does not automatically mean a lower total cost: the new term and any fee also matter. The calculator provides a comparison, not an offer or a recommendation to refinance.
What refinancing changes
The existing-loan estimate uses its balance, annual rate, and months remaining to calculate a level monthly payment and total interest. The proposed-loan estimate uses the same balance plus the entered refinance fee, along with the new rate and term.
Because the fee is added to the new principal, it is included in the proposed repayment schedule. A longer term can reduce the monthly payment while increasing the time over which interest accrues. A shorter term can raise the monthly payment while reducing total interest, depending on the rates and other inputs.
Inputs and assumptions
- Current balance, rate, and months left: Enter the remaining balance and terms of the loan you have now.
- New rate and term: Enter the proposed annual rate and repayment term in months. The calculator accepts terms from 1 to 600 months.
- Refinance fee: Enter a fee from $0 to $5,000. The model adds it to the new loan principal.
- Federal-loan checkbox: Select it if the loans being refinanced are federal. The result then displays a warning about potential loss of federal benefits. This is a user-selected warning, not an eligibility check.
The calculator accepts one current rate and one current term, and this is the limitation stated in full: it does not calculate a weighted average or model each of several loans separately, so a single combined input cannot capture cash flows that differ by balance, rate, or remaining term. One workaround fits many multi-loan cases: compute the weighted average rate yourself and enter the total as one loan. With $20,000 at 4% and $30,000 at 6.5%, the blended rate on $50,000 is 5.5%. Entered as one $50,000 loan at 5.5% over 120 months, the tool estimates a payment of $542.63 and $4,549.32 less total interest than the 7% current loan above. It is an approximation that smooths differences away, and it can misstate loans whose remaining terms differ sharply; for the exact positions, run each loan separately.
How to read the comparison
The monthly payment difference shows whether the proposed payment is lower or higher than the current estimate. Total interest compares interest over each modeled loan's full repayment term. The total savings figure compares total payments, including the new loan fee; it is different from the interest-savings figure, which excludes that fee.
For example, a $50,000 balance at 7% with 120 months remaining has an estimated payment of $580.54 and $19,665.09 in interest. At 4.5% over the same 120-month term with no fee, the estimated payment is $518.19 and interest is $12,183.05. The modeled payment is $62.35 lower per month, and total interest is $7,482.04 lower.
If the same balance is refinanced at 4.25% over 60 months, the estimated payment is $926.48, which is $345.94 more per month than the current payment. The modeled total interest is $5,588.67, or $14,076.42 lower than the current loan's interest over its remaining 120 months. The shorter term requires a larger monthly budget commitment. This 60-month payment differs from the table below's 60-month row because the rates differ: this worked example refinances at 4.25%, while the table holds the rate at 4.50%.
The term decides whether a lower rate saves money
Holding the same $50,000 balance, the 7.00% current loan with 120 months left, and a 4.50% refinance rate with no fee, only the new term changes:
| New term | New payment | Change against $580.54 | New total interest | Total savings against the current loan |
|---|---|---|---|---|
| 60 months | $932.15 | +$351.61 | $5,929.06 | +$13,736.03 |
| 120 months | $518.19 | -$62.35 | $12,183.05 | +$7,482.04 |
| 240 months | $316.32 | -$264.22 | $25,917.93 | -$6,252.84 |
All three rows cut the rate by 2.5 points, and one of them still costs more than the loan it replaces. The 240-month row lowers the payment by $264.22 and adds $6,252.84 of cost, because the balance is carried for an extra ten years. The 60-month row is the cheapest total and the most demanding payment. This is the whole argument for comparing total cost rather than the monthly figure or the rate alone, and it is the reason the calculator shows both.
When a fee is entered and the new monthly payment is lower, the calculator's break-even estimate divides the fee by the monthly payment reduction and rounds up to a whole month. It is a simple fee-payback measure; it does not account for every difference in total interest, loan timing, taxes, or the value of keeping federal protections.
A $500 fee on the 120-month refinance shows how the measure behaves. The fee is added to the new principal, which lifts the payment from $518.19 to $523.37 and shrinks the monthly reduction from $62.35 to $57.17. Dividing $500 by $57.17 gives 8.75 months, so the tool reports a 9-month break-even. Nine months is when the fee has been recovered in monthly cash flow. It is not a statement that the refinance pays for itself by then, because the comparison still runs for the full 120 months, and it says nothing about the federal benefits a private refinance may cost.
Federal-loan considerations
Refinancing federal student debt into a private loan can make the refinanced balance ineligible for federal repayment plans and benefits, which may include income-driven options or Public Service Loan Forgiveness. Private loans generally do not provide the same federal program terms. A private refinance may be difficult or impossible to reverse back into a federal loan.
The trade-off is easier to see as an illustrative pair than as a slogan. For a borrower whose income is low enough, an income-driven plan can set the required payment far below a standard amortizing one, in some cases to $0, while the refinance modeled here locks in the fixed payment on screen, such as the $518.19 over 120 months in the example above. The fixed payment is certain and repays the balance on schedule; the income-driven payment is smaller exactly when income is small, recertifies periodically, and can leave a balance for forgiveness. Which side wins depends on income stability, career path, and forgiveness prospects, none of which this calculator models.
If you indicate that the current loans are federal, the calculator displays a warning. It does not verify loan type, evaluate your eligibility for a program, or estimate the value of a benefit you might give up. Before acting, confirm your loan type and current options with your federal loan servicer or official guidance.
For federal-loan refinancing considerations and the potential effect on federal benefits, review the Federal Student Aid guidance on refinancing federal student loans before making a decision.
Limits of the estimate
The model treats each rate as a fixed annual rate for the calculation. It does not compare fixed and variable offers, predict future rate changes, or calculate credit approval or eligibility. It also does not include costs beyond the entered refinance fee or account for benefits and protections that may be lost.
As practical guidance rather than underwriting advice: most refinance lenders offer prequalification with a soft credit check, so comparing several offers typically does not affect credit the way full applications can; confirm how each lender handles it, since practices vary. Compare offers at the same term length so the rates are comparable, check whether a quoted rate includes autopay or relationship discounts, and read the cosigner-release terms if a cosigner is involved, because release criteria and waiting periods vary by lender and some loans do not offer release at all.
For a broader payment estimate, use the Student Loan Calculator. To compare a payoff strategy, use the Loan Payoff Calculator. For a wider debt-payment comparison, try the Debt Consolidation Calculator.
Last verified: October 2026. Calculator figures are outputs for the inputs entered; they are not live quotes, current rates, or an offer.