Student Loan Payoff Calculator
Federal student loan borrowers have access to eight repayment plans — and the difference in total cost between them can exceed $50,000 on a $60,000 loan balance. Standard repayment minimizes total interest. Income-driven plans lower monthly payments but extend the loan's life and increase total interest paid (with possible forgiveness at 20-25 years). This calculator shows the full payoff comparison across all plans so you can choose based on your actual cash-flow needs and career trajectory.
$16,115 = AGI $50,000 − 225% × $15,060 poverty guideline. The income-driven payment is 10% of this, divided by 12.
| Plan | Monthly Y1 | Total paid | Total interest | Forgiven | Tax on forgiveness | Net total cost |
|---|---|---|---|---|---|---|
| Standard (10-yr) | $666 | $79,935 | $19,935 | — | — | $79,935 |
| Extended (25-yr) | $387 | $115,974 | $55,974 | — | — | $115,974 |
| Income-Driven (IDR) | $134 | $66,582 | $91,619 | $85,038 | $18,708 | $85,290 |
| IDR + PSLFLowest net cost | $134 | $23,434 | $41,726 | $78,291 | — | $23,434 |
Shorter bar = lower net total cost over that plan’s horizon. A plan that forgives a balance shows a lower net cost only after its (taxable) tax-bomb is added back in — PSLF forgiveness, by contrast, is tax-free.
View the TypeScript implementation on GitHub: packages/calc/src/student-loan-payoff.ts · view tests
What this means
The four plans here are not just four monthly payments — they are four entirely different financial trajectories for the same balance. Standard and Extended fully repay the loan and accrue ordinary interest, so their net cost is simply what you pay. Income-driven plans set a payment as a slice of your discretionary income and can run for twenty years, often leaving a balance forgiven at the end — but under current law that forgiven balance is taxed as income. PSLF is the exception: ten years of qualifying payments, then tax-free forgiveness.
In my experience, the single number that decides this comparison is whether you qualify for PSLF. When you do, the math is rarely close — paying the lowest income-driven amount for ten years and walking away from the rest, tax-free, almost always wins on net cost. I’ve found the trap is the opposite case: a borrower on a standard income-driven plan watches their balance grow under negative amortization for two decades, then gets hit with a five-figure tax bill on the forgiven amount. The forgiveness feels like relief; the tax bomb is the part nobody budgeted for, and this calculator puts it right in the table.
I’ve seen people choose a plan on the monthly payment alone and pay tens of thousands more over the life of the loan. The honest framing isn’t “which plan is best” — it’s “what am I optimizing for: the lowest monthly cash outflow now, or the lowest total cost over the life of the loan?” The arithmetic answers the second; your cash-flow reality and career trajectory decide the first. And because the SAVE plan was under legal challenge in 2024, confirm what is actually available to you at studentaid.gov before you enroll in anything.
Worked example
A $60,000 balance at 6%, with an AGI of $50,000, a family of one, the 2024 one-person poverty guideline of $15,060, a 225% discretionary multiplier, a 10% income-driven payment, a 20-year forgiveness horizon, 3% income growth, and a 22% marginal tax rate.
Discretionary income = $50,000 − 2.25 × $15,060 = $50,000 − $33,885 = $16,115. The income-driven payment starts at $16,115 × 10% ÷ 12 = $134/month.
Standard (10-yr): $666/month, $79,935 total paid, $19,935 interest — paid off in 120 months, nothing forgiven. Extended (25-yr): $387/month, $115,974 total paid — the lowest monthly payment of the amortized options, but the most interest ($55,974) by far.
Income-Driven (IDR): that $134 payment is well below the ~$300/month of interest the balance accrues, so the balance grows for twenty years. You pay $66,582, then $85,038 is forgiven — and taxed at 22% for a $18,708 tax bomb, for a net total cost of $85,290. IDR + PSLF: the same $134-ish payments, but only for 120 months — $23,434 paid — then $78,291 forgiven tax-free, for a net total cost of just $23,434.
Result: if you qualify for PSLF, it is the lowest net cost by a wide margin — $23,434 versus $79,935 for Standard. If you do notqualify for PSLF, Standard is the cheapest of the remaining options ($79,935), because the IDR tax bomb pushes its net cost ($85,290) above what you’d pay just amortizing the loan. Same loan, same income — the entire answer turns on PSLF eligibility. Confirm yours at studentaid.gov.
Frequently asked questions
The information and tools on this website are for general educational purposes only and do not constitute financial, investment, legal, or tax advice. Consult a licensed professional for decisions specific to your situation.