Student Loan Repayment Calculator 2026 | Amortization & Payoff ROI

The workbench models five strategies simultaneously: (1) Standard 10-year payoff — the benchmark amortized payment to clear your full balance in 10 years at your current rate; (2) IDR/forgiveness path — a household income-adjusted payment estimate using the SAVE plan’s 225% poverty guideline, with a tax-bomb estimate for non-PSLF forgiveness; (3) Current + extra payments — your current payment plus any monthly extra, annual lump sum, and one-time payment you enter; (4) Refinance all loans — a new private loan covering your full balance at the quoted rate and term; (5) Refinance private loans only — refinancing only the private portion while keeping the federal balance on its current path. Each strategy gets a composite score and the best fit is recommended.

The tax bomb is the income tax liability that arises when student loan balances are forgiven at the end of an IDR plan (20 or 25 years, depending on the plan and your first loan disbursement date). The forgiven amount is treated as ordinary taxable income in the year of forgiveness — so a borrower with $45,000 forgiven in the 24% tax bracket owes roughly $10,800 in additional federal income tax that year. Note that PSLF forgiveness is explicitly tax-free. The workbench estimates your tax bomb using your entered forgiveness horizon and tax rate — not to scare you away from IDR, but to ensure you factor this real cost into the comparison.

The workbench estimates your IDR-style payment using the SAVE plan formula: your payment is approximately 10% of your annual discretionary income divided by 12, where discretionary income = AGI minus 225% of the federal poverty guideline for your family size. If you are married and filing jointly, the workbench adds your spouse’s income to your AGI for this calculation, which reflects how the SAVE plan treats household income for MFJ filers. This is a planning estimate — your actual IDR payment is set by your servicer after official income certification, which considers your most recent tax return or alternative income documentation.

Extra payments on federal student loans are automatically applied to accrued interest first, then to your highest-interest loan balance (under standard servicer rules), unless you specify otherwise in writing. To maximize interest savings, request in writing (email or your servicer’s online portal) that extra payments be applied directly to principal on your highest-rate loan after covering accrued interest. The workbench assumes all extra payments reduce principal after covering that month’s interest, consistent with optimal payment targeting. Always confirm your servicer’s allocation policy.

PSLF (Public Service Loan Forgiveness) forgives the remaining federal Direct Loan balance after 120 qualifying monthly payments made while working full-time for a qualifying employer — government agencies, 501(c)(3) nonprofits, and certain other public service organizations. Forgiveness is tax-free. The workbench uses the PSLF flag to set the tax-bomb estimate to $0 (since PSLF forgiveness is not taxable) and increases the risk penalty for refinancing strategies, because refinancing federal loans permanently forfeits any accumulated PSLF qualifying payments. The PSLF strategic value estimate is based on approximately 35% of the federal balance — a simplified proxy for the forgiveness potential. Use studentaid.gov/pslf for the official PSLF Help Tool.

The annual income growth rate adjusts the long-run IDR total cost estimate. If your income grows over the forgiveness horizon, your IDR payments will grow too — meaning less balance survives to be forgiven and the tax bomb is smaller. The workbench applies a growth-adjustment factor to the estimated forgiven balance: higher income growth reduces the estimated forgiven amount and tax bomb. This makes IDR forgiveness progressively less attractive relative to accelerated repayment as your income growth rate increases. Try 0%, 3%, and 6% to see how sensitive the best-strategy recommendation is to your income trajectory.

Under the SAVE plan, married borrowers filing jointly have their IDR payment calculated on combined household income — which can be substantially higher than income alone, raising the IDR payment significantly. Married borrowers filing separately have their IDR payment calculated on their income only — which can dramatically reduce the IDR payment but may cost more in other taxes (losing the child tax credit, mortgage interest deduction on joint returns, etc.). The workbench models the MFJ scenario directly by adding spouse income to AGI when “Married” and “Filing Jointly” are selected, and uses AGI alone for “Married Filing Separately.” Consult a CPA familiar with the student loan / tax filing tradeoff before changing your filing status based on this estimate.

The one-time payment field models a single lump-sum principal payment — an inheritance, bonus, asset sale, tax refund larger than the annual lump sum, or any other windfall — applied immediately at the start of your accelerated repayment path. The workbench subtracts this amount from the opening balance before running the payoff calculation, then shows how much sooner you’d pay off and how much interest you’d save versus making no one-time payment. This is useful for deciding whether to apply a windfall to student debt or invest it elsewhere — the interest savings rate equals your loan rate, which is a risk-free guaranteed return.

Each strategy receives a composite score based on four penalty factors added to its estimated total cost: (1) a payment stress penalty for any payment above your safe payment cap (income × safe ratio); (2) a PSLF or forgiveness risk penalty for strategies that forfeit federal benefits; (3) an emergency fund penalty applied to aggressive repayment strategies when reserves are thin (under 3 months); and (4) a tax-bomb cost for the IDR forgiveness path when not pursuing PSLF. The strategy with the lowest composite score is labeled “Best Strategy.” Lower total cost, lower payment stress, lower benefit-loss risk, and adequate emergency reserves all favor a lower composite score.

The workbench uses the SAVE plan formula as a planning estimate. Actual IDR payment amounts are set by your federal loan servicer based on official income certification (most recent tax return or alternative income documentation), family size, loan type, and disbursement dates. IDR plans other than SAVE (PAYE, IBR, ICR) use different formulas and poverty guideline multipliers. The workbench’s estimate should be treated as a directional planning number — verify your actual IDR payment at studentaid.gov/loan-simulator for an official estimate.

Yes. Enter your full balance as the private balance and $0 as the federal balance. The IDR-style payment estimate will still calculate (as a what-if), but the PSLF strategic value and tax-bomb will both be $0 since there are no federal loans. The most relevant strategies for all-private borrowers are standard payoff, current + extra payments, and all-loan refinance. Since private loans have no federal protections to preserve, the refinance risk score for all-private borrowers is lower, making refinancing more likely to score as the best strategy if the rate savings are meaningful.

The weighted interest rate is the balance-weighted average of all your loan interest rates. Calculate it as: (Loan 1 balance × rate 1 + Loan 2 balance × rate 2 + … + Loan N balance × rate N) ÷ total balance. For example, if you have $40,000 at 5.5% and $30,000 at 8.0%, the weighted rate is ($40,000 × 5.5% + $30,000 × 8.0%) ÷ $70,000 = ($2,200 + $2,400) ÷ $70,000 = 6.57%. The workbench uses this single rate for all payment and interest calculations, which is a reasonable approximation when rates are not dramatically different across your loans.

Refinance fees / credits net is the refinancing lender’s origination fee minus any lender credit or cash-back bonus they offer. Most major student loan refinance lenders charge no origination fee — but some charge 1–3% of the loan amount. Lender credits (cash bonuses for signing) reduce this net figure and can make the transaction cheaper upfront. The workbench adds this net amount to the refinanced principal, which slightly increases the refinance payment and allows the break-even calculation to reflect the real out-of-pocket cost of the transaction.

For married borrowers pursuing PSLF, the workbench notes that Married Filing Separately (MFS) can significantly reduce the IDR payment used as the PSLF qualifying payment — since MFS excludes spouse income from the IDR calculation. A lower IDR payment means smaller qualifying payments and potentially more forgiveness at the 120-payment mark. However, the tax cost of MFS (losing joint tax benefits) must be weighed against the IDR payment reduction. The workbench models the payment impact — a CPA should evaluate the full MFS vs. MFJ tax cost in your specific situation.

The safe payment ratio is your self-defined threshold for what percentage of gross monthly income is acceptable to spend on student loan payments. Financial planners generally recommend 10–15% for student loans specifically (lower than general DTI guidance because student loans compete with savings, retirement, and quality of life). The workbench flags any strategy whose payment exceeds income × safe ratio with a stress penalty in the composite score. Set it at 10% if you’re prioritizing financial flexibility; 15% if you’re in aggressive debt-payoff mode with stable income and adequate emergency reserves.

This is the number of years until your remaining federal loan balance would be forgiven under a non-PSLF IDR plan. For loans first disbursed before July 1, 2014, IBR forgiveness typically occurs at 25 years. For loans first disbursed on or after July 1, 2014, PAYE and SAVE forgiveness typically occurs at 20 years (for undergraduate loans) or 25 years (for graduate/professional loans). ICR forgiveness is at 25 years. Set this field based on when you first borrowed and which IDR plan you are or intend to be on. When in doubt, use 25 years as a conservative estimate.

No. The workbench uses the PSLF flag as a risk modifier — it increases the risk penalty for refinancing strategies and sets the tax bomb to $0 — but does not calculate or confirm qualifying payment counts. Official PSLF qualifying payment counts are determined exclusively by the Department of Education and your federal loan servicer. Use the PSLF Help Tool at studentaid.gov for official payment tracking and employer certification. Also see the companion PSLF Eligibility & Payment Count Estimator on this site.

The payoff timeline shows “N/A” when the combined payment (current payment plus extra monthly payment) is $0 or is less than the monthly interest accrual on the balance — meaning the loan is not being paid down, it’s growing. Check that your current monthly payment plus extra monthly payment exceeds your balance × (rate / 12). For example, a $70,000 balance at 6.5% accrues $379/month in interest — your combined payment must exceed $379 to make progress. If interest is outrunning payments, focus first on increasing the minimum payment before modeling extra payments.

The private-only refinance strategy applies the quoted refinance rate and term only to the private loan balance (entered separately from the federal balance). The federal balance continues on its current path at the current weighted rate and remaining term. The workbench calculates a blended monthly payment (private refinance payment + federal current-path payment) and a total cost that combines both paths. Since no federal loans are touched, this strategy has the lowest risk score among refinance options — preserving IDR eligibility, PSLF progress, and federal forbearance on the federal portion.

The studentaid.gov Loan Simulator uses your actual federal loan data (pulled from your servicer records) to model IDR plan options and PSLF scenarios — it’s official and data-accurate but covers only federal loan paths. This workbench covers all five strategies simultaneously — including extra-payment acceleration, all-loan refinance, and private-only refinance — and scores them against your household budget, income, and emergency fund cushion in a single integrated analysis. Use both tools: the Loan Simulator for official federal plan options and PSLF payment tracking, and this workbench for the full five-strategy comparison and budget fit scoring. See the full site disclaimer for editorial independence disclosure.