Repayment after the 2025 law · guide
Married borrowers: joint or separate return?
A married borrower earning $45,000 whose spouse earns $65,000 pays $867 a month on the Repayment Assistance Plan if the couple files a joint return, and $100 if they file separately, with their child claimed on the borrower's return. On Income-Based Repayment the gap is similar: $575 against $105 for a borrower who first borrowed after June 2014. Both plans read the adjusted gross income on your federal return, and on a joint return that AGI includes your spouse's income; on a separate return it does not. That rule is written in 34 CFR 685.209(e), unchanged in substance by the 2025 law, which added only that RAP counts, for a borrower filing separately, the dependents claimed on that borrower's own return. Filing separately is not free. It usually raises the couple's income tax and rules out several benefits, including the student loan interest deduction, which a married person filing separately cannot claim at all. The right answer compares the loan saving over a year with the tax cost of the same year.
Joint or separate return: your loan payment
Monthly saving filing separately (RAP)
$767
| RAP, joint return | $867 |
| RAP, separate return (children on your return) | $100 |
| IBR, joint return | $575 |
| IBR, separate return | $105 |
Spouse without federal loans. Separate returns usually cost tax; compare both.
For income-driven plans, the way you file your taxes decides whose income counts. Here is the effect on each plan, and what it costs elsewhere.
Checked by Radif Partners · Editorial policy · How we calculate
The same couple under each filing choice
| Plan | Joint return | Separate return | Monthly difference |
|---|---|---|---|
| Repayment Assistance Plan | $867 | $100 | $767 |
| IBR, borrower since July 2014 | $575 | $105 | $471 |
Over a year the RAP difference is $9,200. That is the figure to set against the tax cost of separate returns. For many couples with similar incomes the tax cost is modest; for couples with very different incomes, filing jointly often saves more tax than separate filing saves on loans. The answer changes from year to year with incomes, which is why it is worth redoing at each recertification.
How each plan reads a married household
RAP and IBR follow the same income rule, set out in 34 CFR 685.209(e)(1): an unmarried borrower, a married borrower filing separately, and a married borrower filing jointly who certifies separation or no reasonable access to the spouse's income use only their own income; other married borrowers filing jointly use combined income. The household is counted differently. IBR uses family size, which includes the spouse on a joint return. RAP uses dependents, which never include a spouse, and on a separate return only those claimed on the borrower's return. A couple with children can therefore decide, within tax rules, which spouse claims them, and the borrower claiming them gains $50 a month per child on RAP.
Two borrowers in one household
When both spouses owe federal loans eligible for the plan, the joint calculation is followed by a split. The couple's payment is multiplied by each borrower's share of their combined principal and interest on eligible loans (34 CFR 685.209(g)). For RAP, each share is then held at a minimum of $10. Couples with two borrowers sometimes find that a joint return costs little on loans, because the combined payment is shared, while still giving them the joint tax rates. The comparison is worth running both ways, using the RAP calculator once with the combined AGI and once with each spouse alone.
The tax side of separate returns
Filing separately changes more than the loan payment. The student loan interest deduction, worth up to $2,500 of income for tax year 2026, is unavailable on a separate return under section 221 of the tax code. Several other benefits shrink or disappear for separate filers. Because those amounts depend on the whole tax return, this site does not estimate them; it shows the loan side precisely, so that a tax preparer can compare a known yearly loan saving with the tax cost of separate returns. The interest deduction page gives the 2026 rules.
Why the RAP gap can be so large
RAP applies one rate to the whole AGI, and the rate rises with income. Adding a spouse's $65,000 to a borrower's $45,000 does not just add the spouse's share at the borrower's rate; it moves the household from the 4% bracket to the 10% bracket, applied to all $110,000. That is how a joint return turns a $100 payment into $867. IBR behaves more gently because it charges a flat percentage on income above the poverty line, so each extra dollar of spousal income adds the same ten or fifteen cents a year. Couples on RAP should therefore expect larger swings from the filing choice than couples on IBR, and it is the main reason a married borrower on RAP should run both cases before every recertification.
The swing works in reverse after a spouse loses a job or leaves the workforce. When the borrower is the only earner, a joint return gives the joint tax rates and, for RAP, the same AGI a separate return would have used, since the other spouse adds nothing. In that year, filing jointly usually wins on both fronts, and the separate-return question returns only when the second income does.
Community property states
In community property states, separate returns split certain income between spouses under state law, which can change the AGI each spouse reports and therefore the income-driven payment. The calculations on this site take the AGI you enter as reported on your return and do not apply community property rules. If you live in such a state and file separately, enter the AGI shown on your own separate return.
Separated or unable to reach your spouse
The regulation has a specific path for borrowers who file jointly but whose household reality differs: a borrower who certifies being currently separated from the spouse, or unable to reasonably access the spouse's income, has the payment computed on their own income alone. A borrower whose marriage ended or who separated after filing can also ask for a recalculation based on alternative documentation of current income, without waiting for the next tax return. That matters most in the year of a separation, when last year's joint return no longer describes the household.
When to revisit the choice
The comparison is not a one-time decision. Each year the income-driven payment is recalculated on the latest return, so the filing choice of that year drives the next twelve months of payments. A raise for the higher earner, a new child, a spouse who starts repaying their own loans or who leaves for graduate school, all change which return wins. Borrowers aiming for Public Service Loan Forgiveness have the strongest reason to keep payments low and should look at separate filing each year; borrowers who will repay in full may care more about total cost. The plan comparator accepts a spouse's AGI on a joint return, so both cases can be compared in a minute.