RAP vs IBR: The Only Legacy IDR Left

The two formulas, side by side

Three borrowers, decided

The $32,000 single borrower with 2 kids — IBR, easily

Family of 3, 150% of poverty = $40,980. IBR payment: $0 (income below the shield). RAP: 3% bracket → $80 − $100 dependents → floor → $10. Ten dollars isn't hardship, but IBR's $0 also counts toward forgiveness — a free clock. The catch: IBR's interest accrues on a growing balance while RAP's waiver would freeze it. If forgiveness is the realistic endgame anyway, the growing balance mostly just grows the eventual taxable forgiveness. Close call in spirit, IBR on points.

The $58,000 old-IBR borrower, 14 years of payments banked — IBR, decisively

Old IBR (15%): pays 15% of ($58,000 − $23,940) = $426/mo, capped at their 10-year Standard. RAP: 5% bracket = $242/mo — nearly half. But this borrower is 11 years from IBR's 25-year forgiveness with credit that carries, versus restarting into a 30-year horizon where credit flows in but the endpoint sits 16 years out. Paying $184/month more to finish 5 years sooner and forgive a larger remaining balance is usually the winning trade. This is the profile that should be most suspicious of RAP's lower sticker payment.

The $75,000 borrower, 3 years into repayment, $95,000 balance — RAP

New IBR: 10% of ($75,000 − $23,940) = $426/mo, interest at 6.5% on $95k = $515/mo — balance grows $89/month on IBR. RAP: 7% bracket = $438/mo, similar payment, but unpaid interest waived and the balance guaranteed to fall. Seventeen years from either forgiveness clock (20-yr IBR vs 30-yr RAP with 3 years credited), the balance math dominates: RAP.

The rules of thumb

• Deep clock credit (12+ years of IDR history) → IBR. The 20/25-year horizon is your most valuable asset; don't dilute it.
• Income under ~150% of poverty for your family size → IBR for the $0 payments, unless watching the balance grow is intolerable.
• Payment under-water against interest (balance × rate ÷ 12 exceeds your payment) and early in repayment → RAP. The waiver is worth thousands a year to you.
• PSLF trackers → whichever payment is lower; both qualify, both forgive tax-free at 120. Usually RAP for middle earners, IBR for low earners.
• Might borrow again for school → decide that first. One new loan after 07.01.2026 deletes IBR from your menu retroactively.

Model your own AGI, family size, and IBR vintage in the calculator — it computes both plans side by side with the 2026 poverty guidelines built in.

The full payment matrix (single borrower, 2026 guidelines)

*IBR caps at your 10-year Standard payment, so high-AGI figures may be lower in practice depending on balance — the cap is IBR's sleeper feature and the reason it can beat RAP at high incomes despite the uglier headline percentage. Patterns to notice: below ~$30,000 IBR wins on payment; the $35,000–$70,000 band is where RAP beats new IBR modestly and crushes old IBR; above ~$75,000 the IBR cap starts flipping the ranking back. Family size shifts every IBR number down (bigger poverty shield) while shifting RAP down only $50 per dependent — large families push the crossover points higher.

The clock-credit fine print that decides close calls

Both plans count your prior qualifying IDR payments — but toward different finish lines (240/300 for IBR, 360 for RAP), and the asymmetry NCLC flags means credit moves into RAP's count more freely than back out. Translate your history before deciding: take your official qualifying-payment count and compute months-to-forgiveness under each plan from today. A borrower with 150 qualifying months is 90–150 months from IBR forgiveness but 210 from RAP's. At a $200/month payment difference, finishing 8 years sooner on IBR is worth far more than the monthly savings — but the same math with 30 qualifying months often favors RAP, because 27 years vs 22 matters less when the waiver is saving you $2,000+/year the whole way. There's no shortcut around doing this arithmetic with your own count; it's five minutes and it's the decision.

Can you switch later if you choose wrong?

Partially — and the asymmetry should shape your default. IBR remains open to you only while all your loans predate July 1, 2026: take one new federal loan and IBR is gone from your menu permanently, with RAP the only IDR for everything. Moving IBR→RAP is generally available; moving RAP→IBR is possible while you retain eligibility but the credit-transfer limits apply. Practical rule: if you're genuinely torn and expect no new borrowing, IBR preserves more optionality as the starting choice — you can defect to RAP later with your credit intact, while the reverse trip is lossier. If any chance of school remains, the choice may be made for you the day you sign the next master promissory note.

The crossover point, located

The two formulas cross, and knowing which side you're on decides the plan. IBR (new-borrower version) charges 10% of discretionary income — AGI minus 150% of the poverty line (~$23,475 for a single filer) — while RAP charges its bracket percentage of total AGI. Run a single filer across incomes: at $35,000, IBR bills ~$96/month against RAP's $87 — nearly a tie. At $50,000, IBR ~$221 vs RAP $208 — still close. At $80,000, IBR ~$471 vs RAP $533 — IBR pulls ahead. Add two kids at $50,000 and RAP drops to $108 (the $50 deductions) while IBR's poverty-line shield for a family of three cuts its bill to ~$40 — IBR wins the low-income family case decisively. The pattern: IBR's shield beats RAP's brackets for lower earners and bigger families; RAP closes the gap as income climbs — and RAP alone carries the waiver and $50 match. Forgiveness timing seals many verdicts: IBR forgives at 20–25 years versus RAP's 30.