How to Calculate Your Roth IRA Contribution: Limits and Formula

To calculate your Roth IRA contribution for 2026, start with the base limit — $7,500 if you’re under 50, or $8,600 if you’re 50 or older — then check your modified adjusted gross income (MAGI) against the phase-out range for your filing status. Below the range, you contribute the full amount. Inside the range, you run a short formula to find your reduced limit. Above the range, direct Roth contributions aren’t allowed.¹

The Three Numbers You Need First

Before you can calculate anything, gather three inputs: your earned income, your MAGI, and your filing status.

Earned income. Your contribution cannot exceed what you earned from work. Wages, salaries, tips, bonuses, commissions, and net self-employment income all qualify. Graduate and postdoctoral fellowship stipends included in gross income count, as does military differential pay and nontaxable combat pay. Taxable alimony from a divorce agreement executed on or before December 31, 2018, also counts. What doesn’t: dividends, interest, rental income, pension payments, deferred compensation, and income from a partnership where you aren’t actively providing services.² If you earned $4,000 for the year, $4,000 is your ceiling regardless of any other rule.

A working spouse’s compensation can support a nonworking spouse’s IRA if you file jointly, as long as combined contributions don’t exceed the working spouse’s taxable compensation.

MAGI. For most W-2 employees, MAGI equals the AGI on your Form 1040. The IRS makes you add back a handful of items: the foreign earned income exclusion, the foreign housing exclusion or deduction, any student loan interest deduction, the exclusion of savings bond interest from Form 8815, and any traditional IRA deduction you took. Income from Roth conversions is excluded from the MAGI calculation.³⁴

Filing status. The phase-out range you use depends on how you file. Married filing separately has its own trap, covered below.

2026 Base Limits and Phase-Out Ranges

The base contribution limit for 2026 is $7,500 for anyone under 50. If you’ll be 50 or older by December 31, 2026, you can add a $1,100 catch-up contribution for a maximum of $8,600.⁵

This cap covers your combined traditional and Roth IRA contributions for the year. Put $3,000 into a traditional IRA and you can put at most $4,500 into a Roth, assuming you’re under 50.

Then compare your MAGI to the phase-out range for your status:

Single or head of household: $153,000 to $168,000.¹
Married filing jointly or qualifying surviving spouse: $242,000 to $252,000.¹
Married filing separately, if you lived with your spouse at any time during the year: $0 to $10,000. This range is not adjusted for inflation.⁶

If you’re married filing separately and lived apart from your spouse the entire year, the IRS treats you as a single filer for Roth purposes and applies the $153,000 to $168,000 range.

MAGI below the bottom of your range means you can contribute the full base limit. MAGI at or above the top means zero direct Roth contribution. MAGI inside the range means the formula below.

The Reduced Contribution Formula

The math comes straight from the statute and works the same for every filing status, just with different numbers.³

Take a single filer, under 50, with a MAGI of $160,000.

Step 1. Subtract the bottom of your phase-out range from your MAGI. $160,000 − $153,000 = $7,000.
Step 2. Divide by the width of your range. Single filers divide by $15,000. Married filing jointly divides by $10,000. Married filing separately (lived with spouse) also divides by $10,000. Here: $7,000 ÷ $15,000 = 0.4667.
Step 3. Multiply by your base contribution limit. 0.4667 × $7,500 = $3,500.
Step 4. Subtract that result from your base limit. $7,500 − $3,500 = $4,000. That’s your reduced Roth contribution for the year.

If you’re 50 or older, substitute $8,600 for the base limit in steps 3 and 4.

Two rounding rules apply. Round your final answer up to the nearest $10. And if the formula produces any positive amount below $200, you’re allowed to contribute $200. This floor keeps people near the top of the range from being pushed to trivial amounts.²

If Your Income Is Over the Top of the Range

Being above the phase-out range closes off direct Roth contributions, but not Roth savings altogether. The backdoor Roth strategy uses a nondeductible contribution to a traditional IRA (which has no income limit on contributions) followed by a conversion of that balance to a Roth IRA. Because you already paid tax on the nondeductible contribution, only the earnings portion of the conversion gets taxed.⁷

One warning: the pro-rata rule. If you hold any pre-tax money in traditional, SEP, or SIMPLE IRAs, the IRS treats every dollar you convert as a proportional mix of pre-tax and after-tax across all your IRAs. If 90% of your combined IRA balance is pre-tax, 90% of any conversion is taxable, regardless of which specific account you pull from. The backdoor works cleanly when you have zero existing pre-tax IRA balances.

Nondeductible contributions and conversions get reported on Form 8606, which tracks your after-tax basis so you aren’t taxed on it again later.⁸

What Happens If You Contribute Too Much

Depositing more than your calculated limit — even by a dollar — triggers a 6% excise tax on the excess. That penalty repeats every year the excess stays in the account.⁹

You have two clean ways to fix it before the penalty applies. You can withdraw the excess along with any earnings it produced by your tax filing deadline, including extensions; the earnings portion counts as taxable income for the year of the contribution.¹⁰ Or you can ask your custodian for a trustee-to-trustee recharacterization, moving the contribution and its earnings into a traditional IRA, where the IRS treats the money as if it had gone there from the start.⁷

Miss the deadline and you’ll owe the 6% tax, reported on Form 5329, every year until you either withdraw the excess or absorb it by under-contributing in a later year.¹¹ Accuracy in the calculation is what keeps this from turning into a recurring bill.

1
Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
2
Internal Revenue Service. Publication 590-A (2025), Contributions to Individual Retirement Arrangements (IRAs)
3
Office of the Law Revision Counsel. 26 USC 408A – Roth IRAs
4
eCFR. 26 CFR 1.408A-3 – Contributions to Roth IRAs
5
Internal Revenue Service. Retirement Topics – IRA Contribution Limits
6
Internal Revenue Service. IRS Notice 2025-67, 2026 Amounts Relating to Retirement Plans and IRAs
7
Internal Revenue Service. Retirement Plans FAQs Regarding IRAs
8
Internal Revenue Service. 2025 Instructions for Form 8606 – Nondeductible IRAs
9
Office of the Law Revision Counsel. 26 USC 4973 – Tax on Excess Contributions to Certain Tax-Favored Accounts
10
Internal Revenue Service. IRA Year-End Reminders
11
Internal Revenue Service. Form 5329 – Additional Taxes on Qualified Plans (Including IRAs)