Modified Adjusted Gross Income (MAGI) Calculator

MAGI is a policy tool. AGI is the "official" income number on Form 1040 Line 11, computed after above-the-line adjustments like the traditional IRA deduction and the student loan interest deduction. When Congress designs an income-tested benefit (Roth IRA eligibility, Premium Tax Credit, Medicare IRMAA surcharge, education credits), it does not want the taxpayer to shrink AGI with those same adjustments to squeeze into eligibility. So each provision adds back the specific deductions that would otherwise let taxpayers game the threshold. Each MAGI variant reflects a different set of policy concerns: Roth IRA MAGI adds back deductions that a Roth contributor could otherwise use to hide income; Premium Tax Credit MAGI adds back tax-exempt interest and non-taxable Social Security because subsidised health insurance should be based on economic income, not just taxable income. Same acronym, five different formulas — always check which MAGI the form or worksheet is asking for.

The three overlap heavily but diverge on one or two items each. Roth IRA MAGI (Pub 590-A Worksheet 2-1) adds back the traditional IRA deduction, student loan interest deduction, foreign earned income exclusion, foreign housing exclusion, excluded savings bond interest, and excluded adoption benefits. Traditional IRA deductibility MAGI (Worksheet 1-1) uses the same add-backs except it does not add back the traditional IRA deduction itself — because that would be circular when computing whether the IRA deduction is allowed. Premium Tax Credit MAGI (IRC §36B(d)(2)(B)) adds back only three items: tax-exempt interest, non-taxable Social Security benefits, and foreign earned income excluded from tax — a completely different set. IRMAA MAGI adds back tax-exempt interest to AGI, nothing else. If a form asks for MAGI, read the instructions carefully to see which definition applies.

You have an excess contribution. If you leave it in, IRC §4973 charges a 6% excise tax per year until it is removed. You have three clean ways to fix it before the excise applies for 2025: (1) withdraw the excess plus any earnings attributable to it before the October 15 extended filing deadline for the tax year — the excess is not taxed, but the earnings are taxed as ordinary income; (2) recharacterise the Roth contribution as a traditional IRA contribution (only available for a traditional-vs-Roth choice, and the deadline is also October 15); (3) if you also have a traditional IRA and no other pretax IRA balances, do a "backdoor Roth" — make a non-deductible traditional IRA contribution and convert it to Roth. The backdoor is only clean if you have no pretax traditional IRA balance at year-end, otherwise the pro-rata rule (§408(d)(2)) taxes most of the conversion. Talk to a CPA before doing a backdoor conversion if you have any existing pretax IRA money.

Congress uses the MFS Roth IRA phase-out as a deliberate nudge to file jointly. If married filing separately were treated the same as single ($150,000–$165,000 in 2025), a high-earning spouse could file separately purely to get their own Roth allowance while the joint return was unavailable to them for some other reason. Instead, IRC §408A(c)(3)(B) sets the MFS phase-out to start at $0 and end at $10,000 — meaning almost any MFS filer with meaningful earned income is fully phased out. The one exception in §408A(c)(3)(B)(iii): if you lived apart from your spouse for the entire year, you are treated as single for this purpose and get the full $150,000–$165,000 band. This is the same policy pattern Congress uses across MFS provisions — capital loss deduction, IRA deductibility, education credits — to discourage separate filing except in genuine estrangement scenarios.

No. Roth IRA contributions are made with after-tax dollars — there is no deduction to add back because there was never a deduction in the first place. The Roth contribution never touched AGI, so it is not in the MAGI computation. The traditional IRA deduction is different — that one reduced AGI, so it gets added back when checking Roth eligibility, because Congress does not want a traditional IRA deduction to expand Roth room. In practice, the Roth contribution is what you are trying to size; MAGI is the input, contribution room is the output. If you find yourself typing the Roth contribution into the calculator, you have the direction backward — start over from Form 1040 Line 11 AGI.

Yes, indirectly — traditional 401(k)/403(b) pre-tax deferrals reduce W-2 Box 1 wages before AGI is computed, so they never enter AGI and are not added back for MAGI. That is one of the cleanest ways to bring MAGI down under the Roth IRA phase-out threshold: bump traditional 401(k) deferrals up in the last few pay periods of the year if you can afford it. Roth 401(k) deferrals do not reduce MAGI — they are after-tax like Roth IRA contributions. Similarly, HSA payroll deductions and Section 125 cafeteria-plan pre-tax deductions reduce W-2 Box 1 and therefore MAGI. Above-the-line HSA contributions made outside payroll reduce AGI but do not get added back for Roth IRA MAGI — so they help too. These four levers (traditional 401(k), traditional 403(b), HSA, cafeteria plan) are the main tools taxpayers within striking distance of the phase-out band use to preserve Roth eligibility.