Student Loan Refinance Calculator 2026 | WAIR & Yield Arbitrage

Student loan refinancing means taking out a new private loan to pay off one or more existing loans — federal, private, or both. The new loan (from a private lender) carries a new interest rate, new term, and new servicer. Federal consolidation, by contrast, combines multiple federal loans into a single new Direct Consolidation Loan through the US Department of Education, preserving federal benefits but not necessarily lowering your rate. Refinancing with a private lender can lower your rate, but it permanently converts any federal loans into private debt — removing IDR eligibility, PSLF access, and federal forbearance protections.

Yes — immediately and permanently. PSLF requires payments on federal Direct Loans while enrolled in a qualifying IDR plan and working full-time for a qualifying employer. Refinancing those loans into a private loan removes them from the federal system entirely. Every qualifying payment you’ve made becomes worthless toward PSLF forgiveness the moment the refinance closes. There is no way to reverse this after the fact. This is why the workbench’s PSLF flag and benefit warning score are critical inputs before you consider refinancing federal loans.

The federal-benefit warning score (0–10) is a composite risk signal that the workbench calculates from five inputs: the proportion of your balance that is federal, whether you’re pursuing PSLF, whether you’re enrolled in IDR, whether you need deferment or forbearance flexibility, and your income volatility level. A score of 0–2 means the tradeoff is low-risk. A score of 5–7 means you should proceed with caution and consider the private-only scope. A score of 8–10 means you should strongly consider staying on your federal path for the federal portion of your balance.

Break-even is the number of months it takes for your cumulative monthly savings from the lower payment to equal the upfront cost of refinancing (fees minus any lender credit). If you refinance with $600 in fees and save $50/month, your break-even is 12 months. Until you’ve owned the new loan for 12 months, you haven’t come out ahead yet. If you refinance again, sell the loan concept, or consolidate before break-even, you’ve lost money on the transaction. Most major lenders now offer no-fee refinancing, which makes break-even either immediate or very short.

Variable rates are typically 0.5–1.5% lower at origination than fixed rates, but they reset periodically (usually monthly or quarterly) based on a benchmark index like SOFR. If rates rise, your payment can increase significantly. Fixed rates offer payment certainty for the entire loan term. The workbench flags variable rate selection explicitly in the federal-benefit tradeoff section. Choose variable if: your income is stable, you plan to pay off in under 5 years, and you can tolerate payment uncertainty. Choose fixed if: income is variable, the loan term is long, or payment predictability is important to your budget.

The private-only scope refinances only your private loan balance at the new rate, leaving all federal loans untouched on their current path. This is the recommended strategy for borrowers who have a mix of federal and private loans and want to capture rate savings without giving up federal protections. The workbench models this scope separately and shows the private-only payment, total cost, and benefit-score impact — which is always 0 for federal-benefit risk since no federal loans are touched.

IDR plans (SAVE, PAYE, IBR, ICR) cap your federal loan payment at a percentage of your discretionary income — typically 5–10% — and can reduce your payment to $0 in low-income years. If you refinance into a private loan, your payment is fixed and does not adjust with income. For borrowers with income uncertainty, career transitions, or family changes, losing IDR flexibility can be more expensive than any interest rate savings from refinancing. The workbench’s “Using IDR?” and “Income Volatility” flags quantify this risk in the benefit score.

A full refinance application triggers a hard credit inquiry, which may temporarily reduce your credit score by a few points. Rate-shopping with multiple lenders within a 14–45 day window (FICO’s “de-duplication” period) typically counts as a single inquiry rather than multiple separate hits. Pre-qualification tools (soft pulls) have no credit score impact. After approval, the new loan appears as a new account and the old loan(s) show as paid off — which can temporarily affect average account age but generally has minimal long-term impact on credit for borrowers with good standing.

This field captures the estimated dollar value of federal loan forgiveness you might still receive if you stay on your current path — whether through PSLF after 120 qualifying payments, IDR forgiveness after 20–25 years, or other federal programs. Entering an accurate estimate here is critical: if you have $35,000 in expected forgiveness, the workbench factors that as a strategic cost of refinancing federal loans. Without this input, the workbench cannot accurately assess the real tradeoff. Check studentaid.gov for your PSLF payment count or IDR forgiveness timeline.

The workbench uses standard amortizing loan math (principal × monthly rate × compounding over the term) and is mathematically accurate for fixed-rate loans. For variable-rate loans, the estimate assumes the initial rate holds for the full term — actual costs will vary with rate changes. Savings estimates assume you make the minimum payment each month. If you make extra principal payments, total interest will be lower than shown. Always treat the results as planning estimates and verify total cost projections with the actual lender’s amortization schedule before closing.

Current path total paid is an estimate of how much you’ll pay in total (principal + interest) if you remain on your current repayment plan for the full remaining term at your current weighted average rate. It’s the baseline against which all refinance scenarios are compared. If you’re on IDR, this estimate is based on your current payment — actual IDR total may differ because IDR payments change with income recertification each year. The workbench flags IDR as a special case and notes that the current-path estimate is a simplified projection.

The total cash-load ratio is your total monthly fixed obligations — including existing debt, fixed expenses, and the refinance payment — divided by your gross monthly income. It’s a broader solvency check than the payment-to-income ratio alone: it tells you what percentage of your income is already committed to fixed expenses before food, variable spending, and savings. A total cash-load ratio above 60–65% is a warning sign that the refinance payment may leave insufficient financial cushion for unexpected expenses.

No. IDR plans (SAVE, PAYE, IBR, ICR) are exclusively available for federal Direct Loans serviced by the US Department of Education. When you refinance federal loans into a private loan, those loans exit the federal system and IDR eligibility is permanently lost for that balance. Some private lenders offer hardship forbearance programs, but these are discretionary, time-limited, and do not adjust based on income the way IDR does. See studentaid.gov/manage-loans/repayment/plans/income-driven for official IDR plan details.

Total savings is the gross difference between what you’d pay on your current path and what you’d pay on the refinance path over their respective full terms. Net savings subtracts the upfront refinance costs (fees minus any lender credit) from total savings — it’s the real bottom-line benefit after accounting for transaction costs. Net savings is the more meaningful number for evaluating whether a refinance is financially worthwhile. Always look at net savings rather than just monthly payment reduction.

The workbench uses a single weighted average rate for the current loan baseline — which you enter manually. If you have multiple federal and private loans at different rates, calculate the weighted average rate before entering it: (Loan 1 balance × rate 1 + Loan 2 balance × rate 2 + …) ÷ total balance. The workbench’s federal vs. private split inputs (federal balance and private balance) allow the private-only refinance scenario to apply the new rate only to the private portion, keeping the federal balance on its current path.

Most financial planners recommend keeping total student loan payments at or below 10–15% of gross monthly income. The 10% threshold is often cited as “comfortable,” and 15% as the upper limit for borrowers without significant other fixed obligations. Above 15%, student loan payments begin competing meaningfully with savings, housing, and retirement contributions. The workbench lets you set your own safe ratio target and flags immediately if the refinance payment exceeds it.

The math in the workbench applies to any fixed-rate installment loan, including Parent PLUS loans refinanced privately. However, Parent PLUS loans have unique federal considerations: they are eligible for Income-Contingent Repayment (ICR) and PSLF if consolidated into a Direct Consolidation Loan, but they are not eligible for SAVE, PAYE, or IBR in their original form. The benefit-risk flags in the workbench still apply — if the parent borrower has PSLF potential or ICR value, the federal-benefit warning score will reflect that.

The federal student loan interest deduction (up to $2,500/year, subject to income phaseouts) applies to interest paid on qualified student loans — which includes both federal and private student loans used for qualified education expenses. Refinanced private student loans typically retain their status as qualified student loans for this deduction, as long as the refinance proceeds were used to pay off the original qualified student loan balance. However, the deduction phases out at higher incomes. Consult a CPA or see IRS Topic 456 for current rules.

The grace period (typically 6 months for federal loans after graduation) is actually an ideal time to shop for refinance rates — you’re not yet required to make payments, so you can take time to compare lenders, negotiate, and make an informed decision. However, apply the same federal-benefit analysis: if your employer might qualify for PSLF, if your income will be modest early in your career making IDR valuable, or if you anticipate income instability in your first 1–2 years, the federal-benefit protections may be worth preserving even at a slightly higher rate.

Lender refinance calculators are designed to show you the savings from refinancing with that specific lender — they have a built-in incentive to make refinancing look attractive. This workbench is an independent planning tool that explicitly models the costs of refinancing (federal benefit loss, break-even, cash-load risk) alongside the savings. It includes a federal-benefit warning score, PSLF and IDR screening flags, and a strategy comparison across three refinance scopes — none of which a lender calculator would include. It is not affiliated with any lender, and no referral fees or commissions influence its outputs. See the site-wide disclaimer for full disclosure.