How the engine actually calculates your plan
No black box. Here's every plan we model, the formula behind it, and the assumptions we make — so you can check our work and trust the verdict.
What we model
For your inputs, we run a month-by-month simulation of each repayment path available to you and rank them by total out-of-pocket cost over the life of the loan:
- Standard 10-year payoff — fixed amortization, the "just pay it" baseline.
- PSLF on RAP — 120 income-based payments at a qualifying employer, then tax-free forgiveness of the balance.
- PSLF on legacy IBR — same 120 payments, but capped at the 10-year Standard amount (only if you first borrowed before July 1, 2026).
- RAP to forgiveness — income-based payments toward 30-year forgiveness for borrowers not pursuing PSLF.
- Legacy IBR to forgiveness — capped payments toward 20-year forgiveness, where applicable.
- Private refinance — a fixed-rate private loan over the term you specify, which forfeits all federal benefits.
The formulas
Standard / refinance payment uses standard loan amortization: payment = balance × r ÷ (1 − (1 + r)⁻ⁿ), where r is the monthly rate and n is the number of months.
RAP payment follows the 2025 federal law's tiered schedule — 1% of total income for the lowest bracket scaling to 10% above roughly $100,000 of income — divided by 12, then reduced by $50 per dependent child, with a $10 monthly floor. RAP also waives unpaid interest each month, so balances don't grow from negative amortization.
Legacy IBR payment is 10% of discretionary income (income above 150% of the federal poverty line for your family size) divided by 12, and — critically for physicians — capped at the 10-year Standard payment. That cap is why high-earning attendings on legacy IBR often pay far less than they would on RAP.
PSLF assumes 120 qualifying monthly payments under a qualifying plan while you work full-time for a qualifying nonprofit or government employer, after which the remaining balance is forgiven and is not taxed federally.
Your income isn't static, and neither is our model. If you're a resident, we apply your training-years income first, then switch to your specialty-level attending income for the remaining months — because that trajectory is exactly what determines whether forgiveness or payoff wins.
Key assumptions
- Poverty guidelines use the 2025 figures for the 48 contiguous states and DC. Alaska and Hawaii are higher; we note this where relevant.
- Income-driven payments for single and married-filing-separately borrowers use only your income; married-filing-jointly includes spouse income. (The MFS lever can lower legacy IDR payments but usually raises taxes — model both with your CPA.)
- Specialty incomes are median estimates you can and should edit to match your actual offers.
- We don't model future statutory changes, employer-eligibility edge cases, state taxes on forgiveness, or one-off servicer errors.
What we don't do
We don't sell your data, we don't take custody of your money, and we are not your investment adviser or fiduciary. The output is an educational estimate to help you ask better questions — not a directive. The 2026 rules are new and still being implemented by the Department of Education and servicers, so always verify specifics at studentaid.gov and confirm major decisions with a qualified advisor.