RAP vs IBR Calculator (2026): The Income Where It Flips

Every RAP-vs-IBR calculator on the internet gives you two monthly numbers and stops. Here is what that leaves out: a single borrower at $100,000 of adjusted income pays $833.33 a month on RAP and $633.83 on IBR — a $199.50 gap. Multiply out the terms, though, and it is $300,000 versus $152,119. The monthly tool showed you a fifth of the actual decision.

Both formulas are simple enough to run by hand in four minutes, and running them by hand is the only way to see the two things that decide most cases: the exact income at which the cheaper plan flips, and the total the calculator never totals.

The Department of Education's announcement on the SAVE wind-down gives you 90 days from your servicer's notice date to choose. Notices started July 1, 2026 and roll in waves into 2027, so the earliest deadline in the country is September 29, 2026 and yours is probably later. This page is the arithmetic.

The two inputs, and where to find them

Both formulas read the same two things, and nothing else.

• Adjusted gross income (AGI). Line 11 of your Form 1040. Not gross salary, not take-home. If your income has dropped since that return, see the current-income note further down — it is worth hundreds a month.
• Household size. You, your spouse if you file jointly, and your dependents. Dependents matter twice: they raise the IBR shelter and they cut $50 each off RAP.

Step 1: your RAP number

RAP — the Repayment Assistance Plan, the replacement plan Congress created in the same law that ended SAVE — charges a flat percentage of your entire adjusted income. Find your rate by dropping the last four digits of your AGI.

Then subtract $50 per dependent, and stop at $10 — RAP cannot produce a $0 payment no matter how many dependents you have or how low your income runs.

The column that matters most in that table is the one people skim: the payment at the bottom of each band. Because the rate applies to your whole income, the payment jumps by the band threshold divided by 1,200 the moment you cross a line. That is $58.33 a month at $70,000 and $83.33 at $100,000, triggered by a single dollar.

Step 2: your IBR number

IBR shelters a first slice of income and charges 10% of what is left. The shelter is 150% of the 2026 federal poverty guideline for the 48 contiguous states — $15,960 for one person, rising $5,680 for each additional person.

Subtract the shelter, multiply by 10%, divide by 12. Below the shelter the answer is $0, and a $0 IBR month is a qualifying payment toward both income-driven forgiveness and Public Service Loan Forgiveness. Above it, the payment is also capped at what the 10-year Standard plan would charge on your original balance — a cap that binds mainly on smaller balances with higher incomes.

One fork: if your first federal loan was disbursed before the July 2014 cutoff, your IBR uses 15% of the excess and forgives at 25 years rather than 10% and 20. Same arithmetic, two different constants.

Step 3: three profiles, every step shown

Run the arithmetic once and you will never need the calculator again.

Notice that the balance never appeared in either calculation. Neither plan reads it. Your balance decides three other things — whether the IBR cap binds, whether your payment covers the interest, and what the do-nothing placement charges — but it has no effect on the payment either income-driven formula produces.

Step 4: the crossover income — the line no calculator prints

Set the two formulas equal and solve, and a clean rule falls out:

RAP is cheaper only when your adjusted income is above (your IBR shelter − $6,000 × dependents) ÷ (1 − 10 × your RAP rate).

For a single borrower in the 3% band: $23,940 ÷ (1 − 0.3) = $23,940 ÷ 0.7 = $34,200. At exactly $34,200 both plans charge $85.50 a month. A dollar below it, IBR is cheaper. A dollar above, RAP is.

Here is the part that trips up everyone, including the plan-comparison pages written by people who should know better: this is not a single crossing. The IBR shelter never moves, but the RAP rate steps up at every $10,000 line. So each time you cross a band boundary, RAP jumps and the cheaper plan can flip back. The result is a sawtooth, not a curve.

Three things fall out of that table, and they are the whole decision for most borrowers.

Dependents settle it. The IBR shelter grows $8,520 per additional household member; RAP's dependent credit is a flat $50 a month, which is worth $600 a year against a shelter increase worth $852 a year in payment reduction at the 10% rate. Stack three of those and RAP can never catch up. If you have three or more dependents, you can stop reading the grid and apply for IBR.

The RAP-cheaper zone lives just under a band line. Every RAP window in that table ends at a $9,999 and starts partway into a band. That is not coincidence — it is the sawtooth. If you sit in one of those windows, check how close you are to the top of it before you commit, because next year's recertification can push you out of it with a raise.

Above $70,000, single borrowers should stop looking. RAP's rate is climbing toward 10% of every dollar while IBR's shelter holds $23,940 permanently out of reach of the formula. The gap widens with every raise.

Step 5: what the monthly number hides

Two things, and they point in opposite directions. This is where a calculator that only prints monthly payments actively misleads.

The forgiveness horizon (favors IBR)

RAP forgives the remaining balance after 360 qualifying payments — 30 years. IBR forgives after 240 for post-2014 borrowers, or 300 for pre-2014 ones. That decade is worth more than the monthly difference in almost every case.

Take the single borrower at $100,000 with a $145,000 balance, holding income flat in today's dollars so the comparison is clean:

• IBR: $633.83 × 240 payments = $152,119, done in 20 years.
• RAP: $833.33 × 360 payments = $300,000, done in 30 years.

A monthly calculator reports a $199.50 difference. The actual difference is about $148,000 and ten years of your life. Real incomes rise, which changes both totals, but it does not change the direction — the plan with the higher rate and the longer term compounds the disadvantage twice.

The interest waiver (favors RAP)

Now the case that runs the other way. RAP waives any interest your payment does not cover, and adds a principal match of up to $50 a month when the payment applies less than $50 to principal. IBR has neither — SAVE's unpaid-interest subsidy died with SAVE.

The single borrower at $45,000 with a $62,000 balance at 6.5% accrues $335.83 of interest a month:

• IBR at $175.50: the payment covers 52% of the interest. The balance grows about $160 a month — $1,924 a year, going the wrong way.
• RAP at $150.00: unpaid interest is waived and the $50 match applies. The balance falls $50 a month.

A $210-a-month swing in balance direction, on the plan that also has the lower payment. Over a decade that is a $19,240 climb versus a $6,000 descent.

The rule I would apply: if you expect the balance to be forgiven, balance growth is noise and the shorter term plus lower payment wins — that is IBR for nearly everyone. If you expect to actually retire the loan, RAP's interest waiver can be worth a higher payment. The question is not which number is smaller. It is which ending you are heading for.

Step 6: calculate the do-nothing number too

Run this one even though you have no intention of using it, because it is what you get if the 90 days expire. Auto-enrollment cannot place you on RAP or IBR — both require an application — so the default is the Standard Repayment Plan or the new Tiered Standard Plan, both priced off your balance and rate rather than your income.

Set that against the income-driven numbers from Step 3. The household of four at $70,000 with a $45,000 balance chooses between $170.83 on IBR and $511 on a Standard placement. The RAP-versus-IBR question was an $87.50 decision. The apply-versus-don't question is a $340-a-month decision, or $4,080 a year.

And Tiered Standard earns no Public Service Loan Forgiveness credit at any tier, including its 10-year one. A public-service borrower placed there can pay faithfully for three years and end up exactly where they started on the count of 120.

Step 7: recalculate before you submit

Three adjustments change the answer often enough that skipping them is the most common way borrowers overpay.

• Use current income if it is lower. Both plans default to the AGI on your most recent return, which in late 2026 usually means 2025. If you now earn less, submit alternative documentation of current income instead. A borrower whose return shows $70,000 but who now earns $52,000 goes from $408.33 to $216.67 on RAP — two full bands.
• Check your distance to the band line above you. If your AGI sits within about $2,000 above a $10,000 boundary, an above-the-line deduction can pull you back under it. Traditional 401(k) deferrals up to $24,500 in 2026, HSA contributions up to $4,400 self-only or $8,750 family, and the student loan interest deduction up to $2,500 all reduce AGI; Roth contributions do not. A borrower at $70,400 who defers an extra $500 lands at $69,900, falls back to the 6% band, and saves roughly $730 a year on the payment while also cutting the income tax on that $500.
• Confirm which door you can walk back through. Under the One Big Beautiful Bill Act, a borrower who leaves IBR cannot re-enroll after July 1, 2028, and PAYE and ICR disappear entirely on the same date. IBR is the choice you can reverse out of; RAP is the one you may not be able to reverse back into. Anyone whose first federal loan is disbursed on or after July 1, 2026 gets RAP as the only income-driven option.

The calculator, compressed

• RAP: AGI × band rate ÷ 12 − $50 per dependent, floor $10.
• IBR: (AGI − shelter) × 10% ÷ 12, floor $0.
• Crossover: RAP wins only above (shelter − $6,000 × dependents) ÷ (1 − 10 × rate).
• Three or more dependents? IBR, at every income. Skip the arithmetic.
• Single above $70,000? IBR, and the margin grows with each raise.
• Single between $34,200 and $69,999? RAP is cheaper monthly — then decide on the forgiveness horizon and the interest waiver, not the payment.
• Headed for forgiveness? IBR's 240 payments against RAP's 360 usually outweighs any monthly gap.
• Headed for full repayment on a growing balance? RAP's interest waiver plus the $50 principal match is the stronger position.
• Either way, apply. Three weeks before your deadline, not on it. Neither plan can be assigned to you automatically.

The uncomfortable framing underneath all of this arithmetic: for nearly every one of the roughly 7.5 million borrowers leaving SAVE, the payment is going up regardless of which formula returns the smaller number. What the calculator determines is whether you absorb the smallest version of that increase or the largest — and for a public-service borrower, whether the clock toward 120 keeps running at all.

This is educational content, not a recommendation about your individual loans. Payment figures here assume the 48 contiguous states, undergraduate Direct Loans, income held flat in today's dollars, and no cap binding on the IBR result; confirm your own band, shelter, deadline, and plan eligibility at StudentAid.gov and against your servicer's notice before applying. Borrowers with consolidated loans carrying mixed borrowing dates, complicated PSLF employment histories, or already-defaulted accounts should have a student-loan attorney or an accredited nonprofit credit counselor review the file first — consolidation and rehabilitation sequencing errors are expensive and slow to unwind after the fact.