Roth IRA Tax Calculator
Find out how much you can contribute to a Roth IRA and what current tax you'll forgo based on your income and filing status. Useful for high earners approaching phase-out limits.
Last updated: September 2026
Formula below · 2 sources (IRS, Wikipedia) · Updated Sep 2026
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About this calculator
A Roth IRA is funded with after-tax dollars, meaning contributions do not reduce your taxable income today but qualified withdrawals in retirement are tax-free. For 2026, the IRS caps annual contributions at $7,500 (or $8,600 if age 50+, including the $1,100 catch-up) and phases out eligibility at higher incomes. For single filers and heads of household, the phase-out begins at $153,000 and ends at $168,000; for married filing jointly it begins at $242,000 and ends at $252,000; for married filing separately it begins at $0 and ends at $10,000 (not adjusted for inflation). The phase-out shrinks the limit, not your planned amount: Reduced limit = limit × (phaseOutEnd − income) / phaseOutWidth, rounded up to the next $10 and never less than $200 while you are inside the range (IRS Publication 590-A worksheet). Allowable = min(plannedContribution, reduced limit). The tax cost of contributing is then: Tax Impact = allowableContribution × (currentTaxRate / 100), representing the after-tax dollars you commit today in exchange for future tax-free growth. Understanding this trade-off helps you decide between a traditional and Roth IRA.
How to use
Assume you are 45, single, earn $160,000, plan to contribute $7,000, and are in the 22% tax bracket. Your contribution limit is $7,500 (under 50), so the full planned $7,000 is within the limit. Reduced limit = $7,500 × ($168,000 − $160,000) / $15,000 = $4,000 (already a multiple of $10). Allowable contribution = min($7,000, $4,000) = $4,000. Tax impact = $4,000 × 0.22 = $880. This means you pay $880 of tax today on the $4,000 you can put in to fund the account, with all future growth and qualified withdrawals being tax-free.
Frequently asked questions
How does income affect my Roth IRA contribution limit as a single filer?
Single filers and heads of household can contribute the full amount if their modified adjusted gross income (MAGI) is below $153,000 for 2026. Between $153,000 and $168,000 the contribution limit phases out proportionally. Above $168,000, direct Roth IRA contributions are no longer allowed. High earners who exceed the limit can still use a 'backdoor Roth IRA' strategy, converting a non-deductible traditional IRA contribution into a Roth IRA.
What is the difference between a Roth IRA and a traditional IRA for tax purposes?
A traditional IRA may give you a tax deduction now, reducing your taxable income in the year of contribution, but withdrawals in retirement are taxed as ordinary income. A Roth IRA provides no upfront deduction, but qualified withdrawals — including all investment growth — are completely tax-free. The better choice depends on whether you expect your tax rate to be higher now or in retirement. Younger earners in low brackets often benefit most from the Roth option.
Why should I calculate the tax impact before making a Roth IRA contribution?
Knowing the after-tax cost of a Roth contribution helps you compare it against a traditional IRA or other investment vehicles. If your current tax rate is high and you expect a lower rate in retirement, a traditional IRA deduction may save more money overall. Conversely, if you anticipate higher future taxes or want tax-free inheritance for heirs, the Roth is often superior. This calculator quantifies that trade-off so you can make an informed decision rather than guessing.