Student Loan Payoff vs Invest Calculator
Compare aggressive student loan payoff vs investing the extra. Interest rate, expected return, tax bracket, and PSLF/IDR considerations. Free.
Student Loan Payoff vs Invest Calculator
The classic young-professional dilemma: pay down student loans aggressively vs invest the extra. Math: if expected investment return > loan rate × (1 − marginal tax), invest wins. Otherwise payoff wins. Plus behavioral + PSLF + income-driven repayment factors.
Aggressive Payoff
Invest the Extra
How to Use the Comparison
Use realistic loan rate
Federal Direct Loans 2026-27 (Federal Student Aid): 6.52% undergraduate, 8.07% graduate unsubsidized, 9.07% PLUS. Grad PLUS is closed to new borrowers from 1 July 2026 under the One Big Beautiful Bill Act; existing Grad PLUS borrowers can continue for a limited period and none will be awarded from the 2029–30 award year. Private loans: highly variable, 5-15%. Refinanced rates: 4-8% depending on credit. The MATH leans aggressively toward payoff when rate exceeds 7%; invest typically wins at sub-5% rates.
Realistic investment return
Enter the long-run return of the portfolio you would actually hold, after fees — the default here is 7%. Don't anchor on a recent bull-market stretch or on a headline index figure; and remember the tool taxes the gains at 20%, the top US long-term capital-gains rate.
Consider PSLF / IDR if federal
If you work in public service (government, 501(c)(3) nonprofit) and have federal direct loans: pursue Public Service Loan Forgiveness — 10 years of on-time payments → balance forgiven tax-free. Income-driven plans cap payments: the Repayment Assistance Plan (RAP) at 1–10% of adjusted gross income with the balance discharged after 30 years, and IBR at 10% (15% for pre-2014 borrowers) of discretionary income with forgiveness after 20 (25) years (Federal Student Aid). In PSLF or IDR scenarios, aggressive payoff is the WRONG move — minimize payments to maximize forgiveness.
Weight behavioral factors
The math says invest if return > loan rate, but behavioral finance matters. Some people sleep better debt-free; some get demoralized seeing high balances. For psychological well-being, hybrid approach (split monthly extra 50/50 between payoff + invest) is often the right answer — captures math + behavioral benefits.
The Math + Strategy of US Student Loans
The Tax-Adjusted Comparison
The core math: if expected investment return > loan rate × (1 − marginal tax rate, for interest deductibility), invest the extra. Student loan interest is deductible up to USD 2,500 a year on federal taxes, phasing out for 2026 at modified AGI of USD 85,000–100,000 (single) and USD 175,000–205,000 (joint) — IRS Rev. Proc. 2025-32. At the tool's default 24% marginal rate a nominal 6% loan becomes 4.56% effective, which is what the tax-adjusted rate above shows. Two simplifications to keep in mind: the tool applies the adjustment to the whole loan rate, whereas the real deduction stops at USD 2,500 of interest (about USD 41,700 of balance at 6%) and disappears above the phase-out; and it taxes investment gains at a flat 20%.
Above the deduction phase-out there is no tax adjustment — set the marginal-tax input to 0 to model that. For high earners with USD 100K+ student loans (medical/law graduates), the deduction provides minimal relief either way. The straightforward comparison: 6% loan vs 7% expected return = invest wins narrowly. 8% loan vs 7% expected return = payoff wins. At a loan rate of 7% or more the tool returns the payoff verdict regardless of the return you enter, on the view that a guaranteed 7% beats an expected 7%.
PSLF and Income-Driven Repayment
For federal Direct Loans (excludes private + parent PLUS + Perkins), two government forgiveness pathways change the calculus dramatically. Public Service Loan Forgiveness (PSLF): 120 qualifying monthly payments while working full-time at a 501(c)(3) nonprofit or government agency = balance forgiven, tax-free. Best path for: doctors, nurses, teachers, government employees, nonprofit workers. Income-Driven Repayment (IDR): the Repayment Assistance Plan (RAP) sets payments at 1–10% of adjusted gross income, less USD 50 per dependent, with the balance discharged after 30 years; IBR takes 10% of discretionary income (15% for pre-July-2014 borrowers) with forgiveness after 20 (25) years. Under the 2025 One Big Beautiful Bill Act, SAVE is being wound down, PAYE and ICR end no later than 1 July 2028, and borrowers whose loans are all disbursed on or after 1 July 2026 have RAP as their only income-driven option (Federal Student Aid). Best path for: low income relative to debt, growing income trajectory.
In PSLF or IDR scenarios, aggressive payoff is mathematically WRONG. Minimum payments through the qualifying period maximize forgiveness. Aggressive payoff actually reduces the forgiveness benefit (less balance left to forgive). This is the most common student loan strategy error — medical residents paying down loans aggressively that would otherwise be PSLF-forgiven, giving up forgiveness that can run to six figures. Federal loans with PSLF/IDR potential should typically minimize payments; private and non-eligible federal loans should follow the math/payoff calculation.
"Aggressive student loan payoff is mathematically wrong if you'll qualify for Public Service Loan Forgiveness. A USD 200,000 loan at 6% on a 10-year schedule costs about USD 266,000 in total payments; the same borrower making 120 income-based payments under PSLF pays a fraction of that and has the rest forgiven tax-free. Run the PSLF math first."
The Behavioral + Hybrid Approach
Beyond math: some people simply can't sleep with student loan debt. Others get demoralized seeing high balances on their statements. For these borrowers, aggressive payoff has real psychological value even if mathematically suboptimal — the "feeling free" of debt elimination is worth real money. The hybrid approach often wins behaviorally + mathematically: split monthly extra 50/50 between additional loan payment + index fund investment. Captures partial debt-free progress + partial market exposure. A common planner compromise for loans at moderate rates (4-7%) is exactly this split. Above a 7% loan rate, lean toward mostly payoff. Below 4%, lean toward mostly investing.
Refinancing a federal loan destroys forgiveness permanently
US student loans outstanding: USD 1.86 trillion at Q2 2026 (Federal Reserve G.19 consumer credit release) — the largest non-mortgage consumer debt.
Federal Direct Loan rates 2026-27: 6.52% undergraduate, 8.07% graduate unsubsidized, 9.07% PLUS (Federal Student Aid). Grad PLUS closed to new borrowers from 1 July 2026.
Student loan interest deduction: up to USD 2,500 a year, phasing out for 2026 at MAGI USD 85,000–100,000 single / USD 175,000–205,000 joint (IRS Rev. Proc. 2025-32).
Math: invest > payoff when expected return > loan rate × (1 − marginal tax adjustment).
PSLF: 10 yrs of qualifying payments at 501(c)(3)/government employer = balance forgiven, tax-free.
IDR plans: RAP takes 1–10% of AGI with discharge after 30 years; IBR takes 10% (15%) of discretionary income with forgiveness after 20 (25) years.
Federal loans are discharged on death + total/permanent disability. Private loans typically aren't.
Refinancing federal → private loses PSLF/IDR eligibility forever. Only refinance if no PSLF/IDR path applies.
A federal loan is in default after 270 days of missed payments; the whole balance falls due and wage garnishment and tax-refund offset follow (Federal Student Aid).
Bankruptcy: student loans extremely hard to discharge — must prove "undue hardship" (Brunner test).
Frequently Asked Questions
- Depends on loan rate, PSLF eligibility, and your behavioral preferences. Math test: if expected investment return > loan rate × (1 − tax adjustment), invest is better. PSLF test: if you qualify, NEVER pay aggressively — minimum payments maximize forgiveness. Behavioral test: if debt actively stresses you, the psychological benefit of payoff may justify the math sub-optimality.
- Public Service Loan Forgiveness: 120 qualifying monthly payments while working full-time at 501(c)(3) nonprofit OR US government agency (federal/state/local) = remaining balance forgiven, tax-free. Must have federal Direct Loans (consolidate FFEL/Perkins to Direct first). Submit Employer Certification annually to track progress. Best for: nurses, doctors at nonprofits, teachers, government workers, social workers, legal aid. Most-utilized federal student loan benefit.
- SAVE is being wound down under the 2025 One Big Beautiful Bill Act and its enrollees have to move to another plan; PAYE and ICR end no later than 1 July 2028. The Repayment Assistance Plan (RAP) — 1–10% of AGI, less USD 50 per dependent, discharge after 30 years — is the only income-driven plan for borrowers whose loans are all disbursed on or after 1 July 2026. IBR remains for earlier borrowers at 10% of discretionary income (15% for pre-July-2014 loans) with forgiveness after 20 (25) years (Federal Student Aid). Re-evaluate annually as the rules settle.
- Only if NO federal benefit applies (no PSLF eligibility, no IDR need, very high income making IDR irrelevant). Once you refinance federal → private, you lose PSLF + IDR forever. For high-income graduates with stable income + no PSLF/IDR path: refinancing at lower private rate (typically 4-6% vs federal 6-9%) saves significant interest. For everyone else: keep federal.
- Yes — up to USD 2,500 a year on federal taxes, "above the line" (you don't have to itemize). For 2026 it phases out at modified AGI of USD 85,000–100,000 (single) and USD 175,000–205,000 (joint) — IRS Rev. Proc. 2025-32. Within the phase-in it trims the effective loan rate by your marginal rate, on up to USD 2,500 of interest. Above the phase-out the deduction is lost — set the marginal-tax input to 0 to model that.
- Federal: default is declared after 270 days of missed payments; the whole balance becomes due, your credit record is damaged, and the government can garnish wages administratively and offset tax refunds and federal benefits, including Social Security (Federal Student Aid). You can get out through rehabilitation (nine on-time payments) or consolidation. Private: lender sues for collection; can lead to wage garnishment via court judgment. Bankruptcy: extremely hard to discharge (Brunner test requires proving "undue hardship"). Avoid default at all costs — IDR plans can drop payment to USD 0/month if income is low.
- Often the right answer for moderate-rate loans (4-7%). Split monthly extra 50/50: half to extra loan payment, half to index fund. Captures partial debt elimination + partial market upside + emotional benefit of progress on both fronts. For loans above 7%: lean 70-80% payoff. Below 4%: lean 70-80% invest. The hybrid approach is a common recommendation from planners for clients with significant student debt at moderate rates.
- No. ALWAYS capture full employer 401(k) match first. That's a guaranteed 100% return (employer matches your contribution) — beats any reasonable student loan rate. After capturing full match, decide between additional 401(k), aggressive loan payoff, or index investing per the math + behavioral factors above. The order: (1) full 401(k) match; (2) high-interest debt (credit cards 18%+); (3) IRA contributions or extra student loan payoff; (4) max 401(k) + investing.
- Various federal proposals (mass forgiveness, USD 10K cancellation, etc) have been proposed + partially attempted 2021-2024 — most blocked in court. The political landscape is uncertain. Don't strategize around future forgiveness — pay/invest based on current rules + your specific PSLF/IDR situation. If broader forgiveness materializes, treat as upside; don't bet your strategy on it.
- International students (F-1, J-1 visa) typically cannot access federal student loans (no SSN). Must rely on: (a) private student loans (often require US co-signer); (b) school-issued loans; (c) home country government scholarships/loans. Different math: no PSLF eligibility, no federal IDR plans, no US tax interest deduction. After graduation, if staying in the US on an H-1B and earning income, some private lenders will refinance for visa holders at lower rates. Consult a cross-border financial adviser.
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Method & sources
How it computes
Compares two uses of a fixed extra monthly sum over the remaining loan term: (a) paying it into the loan, which shortens the amortisation and then redirects the freed payment into investing at the expected return, versus (b) investing it from day one with the loan left on schedule. Investment gains are taxed at a flat 20%; the verdict compares the expected return with the loan rate × (1 − your marginal tax rate), and a loan rate of 7% or more always returns the payoff verdict.
What this tool implements
- Standard amortisation (monthly compounding) for the loan; annual compounding of end-of-year contributions for the investment side
- Investment gains, not contributions, taxed at a flat 20% — the top US long-term capital-gains rate
- The interest-deduction adjustment is applied to the whole loan rate as a simplification; the real deduction stops at USD 2,500 of interest a year and phases out at MAGI USD 85,000–100,000 (single) / USD 175,000–205,000 (joint) for 2026 — stated on the page
- Context figures: Federal Direct Loan rates for loans first disbursed 1 July 2026–30 June 2027 (6.52% undergraduate, 8.07% graduate unsubsidized, 9.07% PLUS); RAP 1–10% of AGI with discharge after 30 years; IBR 10%/15% of discretionary income with forgiveness after 20/25 years
Sources
- Internal Revenue Service. Rev. Proc. 2025-32, §3.29 Interest on Education Loans — 2026 phase-out USD 85,000–100,000 (USD 175,000–205,000 joint). https://www.irs.gov/pub/irs-drop/rp-25-32.pdf
- Federal Student Aid, U.S. Department of Education. Interest Rates for New Direct Loans (first disbursed on or after 1 July 2026). https://studentaid.gov/announcements-events/interest-rates-for-ne…
- Federal Student Aid, U.S. Department of Education. Income-Driven Repayment Plans (Repayment Assistance Plan, IBR; PAYE/ICR sunset) and One Big Beautiful Bill Act updates. https://studentaid.gov/manage-loans/repayment/plans/income-driven
- Board of Governors of the Federal Reserve System. Consumer Credit — G.19, student loans outstanding (memo item). https://www.federalreserve.gov/releases/g19/current/default.htm
What can make this go out of date
- Federal Direct Loan rates reset every 1 July from the May 10-year Treasury auction (Federal Student Aid publishes them each spring)
- IRS annual inflation adjustments (a Revenue Procedure each autumn) move the interest-deduction phase-out; the USD 2,500 cap is not indexed
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