Student Loan Payoff Calculator
Federal or private, standard or income-driven, in-school capitalization included. Model your actual repayment with the options that matter for student loans — not a generic loan calculator pretending to be one.
Federal vs private — what the calculator handles differently
Federal student loans give you access to income-driven repayment plans (PAYE, IBR, SAVE) that cap your monthly payment at a percentage of your discretionary income and forgive any remaining balance after 20-25 years. Switch the loan type to Federal and check the IDR option to see how that cap compares against the standard repayment math.
Private student loans have none of those options. They're standard installment loans — fixed payment until the balance clears. The calculator treats private loans as such and hides the IDR controls.
Both loan types share grace-period interest capitalization. Federal unsubsidized loans and most private loans accrue interest while you're in school and add it to the principal when repayment begins. Enter the number of grace months to capitalize that interest before the repayment math runs.
When does IDR make sense?
IDR is the right call when your income relative to your balance makes the standard 10-year payment infeasible. A common rule of thumb: if your monthly payment exceeds 10% of your gross monthly income, IDR will be cheaper in the short run.
Where IDR helps: nonprofit and government workers pursuing PSLF (10-year forgiveness), borrowers with high debt-to-income ratios early in their careers, and anyone whose alternative is delinquency or default. Public Service Loan Forgiveness pairs with IDR to discharge any remaining balance after 120 qualifying payments while working in qualifying public service.
Where IDR hurts: high earners who pay the income percentage for 20-25 years often end up paying more in total interest than standard repayment would have cost. IDR also stretches the timeline — even if forgiveness eventually clears the balance, your money is locked up in student-loan payments for two decades instead of investments or other goals.
Frequently asked questions
What's the difference between federal and private student loans?
Federal loans (Direct Subsidized, Direct Unsubsidized, Grad PLUS, Parent PLUS) come from the U.S. Department of Education. They have fixed rates set by Congress, access to income-driven repayment plans, forgiveness programs (PSLF, IDR forgiveness after 20-25 years), forbearance options, and discharge in cases of death or total disability. Private loans come from banks, credit unions, or fintechs. They typically offer lower rates to borrowers with strong credit, but have no IDR caps, no forgiveness, and limited hardship options. Most borrowers should exhaust federal options before considering private.
How does income-driven repayment (IDR) actually work?
IDR plans cap your monthly payment based on income rather than balance. The formula: take your AGI, subtract a 'protected' portion (1.5× to 2.25× the federal poverty line depending on plan and family size), and pay a fixed percentage of what remains — 10% under PAYE/SAVE, 15% under IBR. The cap is divided into monthly installments. After 20 or 25 years of qualifying payments, any remaining balance is forgiven (currently taxable as ordinary income in most cases, though that has varied by year). IDR makes payments manageable on a tight income but stretches the repayment timeline and increases total interest if you ever earn more.
Is the calculator's IDR formula current?
It uses 2025 Department of Education parameters: PAYE/SAVE = 10% of discretionary income (protected income = 1.5× and 2.25× of poverty line respectively), IBR = 15% (protected income = 1.5× of poverty line), with 20-year forgiveness on PAYE/SAVE and 25-year on IBR. Poverty guidelines are the 2025 HHS figures for the contiguous 48 states. Student loan policy has changed several times in recent years and is subject to legal challenges — if you're making plan decisions, confirm current parameters with your loan servicer at studentaid.gov.
What is grace-period interest capitalization?
On federal unsubsidized loans and most private loans, interest accrues during in-school enrollment, the 6-month grace period after graduation, and any forbearance. When repayment starts, that accrued interest is added to (capitalized into) the principal balance. From then on, you're paying interest on interest. The calculator lets you specify how many months of grace/deferment to capitalize so your starting balance reflects reality. Federal subsidized loans don't accrue interest in school or grace, so leave it at 0 for those.
Should I refinance my federal loans into a private loan for a lower rate?
Almost never, unless you have very high income, excellent credit, and zero chance of needing IDR or PSLF. Refinancing federal loans into a private loan permanently forfeits: income-driven repayment caps, Public Service Loan Forgiveness, death/disability discharge, expanded forbearance, and most consumer protections. The interest savings rarely outweigh those losses. Private-to-private refinancing is a different story — that's just a rate shop. If you're considering consolidation, our debt consolidation calculator runs the numbers.
What's Public Service Loan Forgiveness (PSLF)?
PSLF forgives the remaining balance on Direct Loans after 120 qualifying monthly payments (10 years) made while working full-time for a qualifying public service employer — government agencies, 501(c)(3) nonprofits, and a few others. Payments don't have to be consecutive, and they must be on an income-driven plan or the standard 10-year plan. PSLF is more valuable than IDR forgiveness because the timeline is shorter and forgiveness has been explicitly excluded from taxable income. This calculator doesn't model PSLF specifically — for that you need to track qualifying payments at studentaid.gov/pslf.
Related debt tools
Loan Payoff Date Calculator
Generic payoff date for any fixed-APR loan.
Debt Avalanche Calculator
Have other debts too? Avalanche figures out which to attack first.
Debt Consolidation Calculator
Coming soonCompare current debts against a single consolidation loan.
Extra Payment Savings
Coming soonWhat an extra $X/month or one-time lump sum buys you.
Estimates are educational only. Student loan policy — particularly IDR plans, forgiveness rules, and tax treatment of forgiven balances — has changed several times in recent years and remains subject to ongoing legal and legislative challenges. Numbers above use 2025 Department of Education formulas and 2025 federal poverty guidelines. Verify current parameters and confirm plan eligibility with your loan servicer at studentaid.gov before making decisions. This calculator does not model PSLF specifically, mixed federal/private portfolios, or the SAVE plan's unpaid-interest subsidy.