The two limits don't talk to each other, and that is the whole answer
A designated Roth account is a Roth bucket inside an employer plan — a Roth 401(k), Roth 403(b), or the Roth side of a governmental 457(b). It is governed by the plan rules and the elective deferral limit. A Roth IRA is an account you own outside any employer, governed by the IRA rules. Two separate statutory schemes, two separate ceilings. Maxing the plan does not consume any part of the IRA ceiling, and the age-based catch-up amounts run on separate tracks as well.
Where people trip is the aggregation that does exist, one level down. Inside the plan, your Roth deferrals and your pre-tax deferrals share a single elective deferral limit — splitting between them does not double it. Outside the plan, your Roth IRA and any traditional IRA contributions share a single IRA limit for the year. So there are walls inside each container, and no wall between the two containers.
There is also an overall cap on everything that lands in an employer plan in a year, including employer match, profit sharing, and after-tax contributions. That cap matters mainly to owners of a business and to people whose plans allow large after-tax contributions. It has nothing to do with your IRA. Every one of these figures is indexed and moves; treat the specific dollar amounts as something to look up for the current year rather than something you remember from last year.
The Roth IRA has an income gate. The plan Roth does not.
This is the asymmetry that catches high earners. A designated Roth account inside a plan has no income eligibility test — you can earn a very large salary and still direct deferrals to it. A Roth IRA contribution phases out over a modified adjusted gross income range that depends on your filing status. Above the top of that range, the direct contribution is off the table entirely.
So the answer to the question changes depending on a fact about you that the question does not contain. If your income sits below the phase-out, both maximums are available. If it sits above, the plan Roth is available and the direct Roth IRA contribution is not. In the phase-out band, a partial contribution is available and the exact amount depends on where in the band you land — which you often don't know until late in the year.
That uncertainty gets worse in a year with a one-time spike: a business sale, a large bonus, exercised options, a concentrated stock sale. People fund the Roth IRA in January on the assumption that this year looks like last year, then close a transaction in November and discover the contribution was never permitted. Note also that the income definition used for this test has specific inclusions and exclusions that are not the same as your taxable income line — worth confirming the current definition rather than assuming.
There is a well-known indirect route into a Roth IRA for people above the range, using a non-deductible traditional IRA contribution followed by a conversion. It works mechanically, but its tax result depends on every traditional, SEP, and SIMPLE IRA you own, not just the one you contributed to. If you have rolled an old 401(k) into an IRA, that balance is part of the calculation. Confirm the current conversion and aggregation rules with the IRS before treating that route as clean.
In the year you actually retire, your paycheck sets the ceiling
Both Roth vehicles depend on compensation. Plan deferrals can only come out of pay, so if you stop working in March, your deferral capacity is limited to what you earned through March — regardless of what the annual limit says. The Roth IRA contribution is capped by your taxable compensation for the year, and if your earned income for the year is small, the contribution is small.
What counts as compensation is narrower than people expect. Investment income, pension payments, Social Security, and most severance treated as non-wage payments do not create IRA contribution room. Some final payouts do and some don't; this is a question for your plan administrator and your payroll department, not a guess.
There is one useful timing asymmetry here. Plan deferrals must run through payroll by the end of the calendar year, so that door closes with your last paycheck. An IRA contribution can generally be made after year end, up to the tax filing deadline for that year, which means you can decide the IRA side once you actually know your income. People retiring mid-year often discover the plan door shut behind them while the IRA door was still open. If you are married and filing jointly, the household's earned income can support an IRA contribution for a spouse who had no earnings of their own — the rules for that are specific and worth checking.
The catch-up rules are mid-change, so the number you remember may not be the number that applies
Recent legislation reshaped catch-up contributions in employer plans in two ways that matter here. There is a higher catch-up amount for a specific band of ages, and there is a rule requiring that catch-up contributions be made on a Roth basis for participants whose prior-year wages exceeded a set level. Effective dates for these provisions have already been adjusted once by administrative guidance.
The practical consequence is that the answer to "how much catch-up can I make and what tax treatment does it get" depends on the current year, your age, your prior-year wages from that employer, and whether your plan offers a Roth option at all. If a plan has no Roth feature and a participant's catch-up is required to be Roth, the capacity can simply disappear until the plan is amended.
None of that touches the IRA catch-up, which follows the IRA rules and is separate. But it does mean the total Roth capacity available to you this year is not a fixed figure you can carry from memory. Pull the current numbers from IRS guidance and confirm your plan's features in the summary plan description or with the administrator.
The IRA side has a repair window. The plan side mostly does not.
This distinction is worth more than it looks. If you contribute to a Roth IRA and later find you were over the income limit or over the compensation limit, there is a correction path: withdraw the contribution along with attributable earnings by a deadline, or recharacterize the contribution as a traditional IRA contribution. Left uncorrected, an excess IRA contribution carries a penalty that repeats for every year it stays in the account. The correction is available, but it is time-limited and easy to miss because nobody sends you a notice.
Deferrals into a designated Roth account are far less forgiving. Money already deferred cannot be pulled back because you changed your mind about the tax treatment. Excess deferrals require a corrective distribution processed through the plan, on the plan's timeline. And the choice between Roth and pre-tax deferral, once made for a payroll period, is not re-labelable later.
So the sequencing question is real. The plan decision is made early, in payroll, with incomplete information about the year. The IRA decision can be made last, with the year's income known. People who reverse that order — locking the IRA early and leaving the plan election to drift — give up the flexibility they had. Confirm current correction deadlines and recharacterization rules with the IRS, since the rules on undoing conversions and undoing contributions are not the same.
The limit is the easy part. The scarce resource is low-income years.
Here is where this question connects to decisions nobody is holding for you. Payroll owns your deferral election. The IRA custodian owns the contribution. Your accountant sees both in April, after the year is closed. Your investment advisor may only see the balances. Each of them is doing their piece correctly, and the interaction between the pieces is unowned.
The interaction that matters: Roth capacity from contributions is limited, but Roth capacity from conversions is not. Contributions are constrained by limits, income gates, and earned income. Conversions are constrained mainly by how much tax you are willing to pay in a given year and the cash you have on hand to pay it. In the years between stopping work and the start of required distributions, taxable income is often at its lowest, which is precisely when conversion is cheapest. Cash spent maxing a Roth IRA in a high-earning year is cash not available to pay conversion tax in a low-earning year. Both moves put money into a Roth. They do not cost the same.
There is a second interaction that has nothing to do with income tax. Filling both Roth buckets to the limit in your last working years can leave you short of accessible cash afterwards, which forces taxable withdrawals from a pre-tax account in exactly the years you were hoping to keep income low. That can raise a Medicare premium calculated from a prior year's tax return, or change what you pay for marketplace coverage in the years before Medicare starts. The lookback periods and current amounts should be confirmed against the primary sources — the point is that the years are linked, and the link is invisible if each decision is examined alone.
If you ask whether Roth or pre-tax is better, the answer rests on an assumed future tax rate for a household whose future income, filing status, and state of residence are not yet known. That assumption deserves to be stated out loud rather than buried in a projection. Where the withdrawal sequencing side of this sits, we have written about separately.
What to actually do
- Look up the current-year elective deferral limit, IRA limit, catch-up amounts, and Roth IRA income phase-out ranges from IRS guidance — not from a prior-year article or a memory of last year's figures.
- Estimate your modified adjusted gross income for this specific year, including any bonus, business sale, option exercise, or capital gain you expect, and check where it falls relative to the Roth IRA phase-out for your filing status.
- Ask your plan administrator three questions in writing: does the plan offer a designated Roth option, does it allow catch-up contributions, and how does it apply the Roth catch-up requirement for higher-wage participants this year.
- If you are retiring mid-year, calculate the compensation you will actually earn before your last paycheck, and treat that as the real ceiling on both the plan deferral and the IRA contribution.
- Decide the plan election early because payroll requires it, and hold the IRA contribution decision open until you know the year's income — the IRA contribution deadline generally runs past year end, and that timing gap is usable.
- Before funding both to the maximum, price out the alternative: how much of that cash would cover conversion tax in a later low-income year, and whether you will need it as accessible cash between your last paycheck and the start of any pension or Social Security income.
- Write down the assumed future tax rate that makes Roth funding worth it for your household, and keep it where you can revisit it when income, filing status, or state of residence changes.
How this shows up
A couple in their early sixties both max their Roth 401(k)s and both fund Roth IRAs in January. In October, one of them sells a minority stake in a partnership. Their income for the year lands above the Roth IRA phase-out. The deferrals were fine — plan Roth accounts have no income test — but both IRA contributions were never permitted, and the correction has to happen before a deadline nobody flagged.
A single filer retires in April with a large accrued bonus and unused vacation paid out in the final check. She assumes the payouts create IRA contribution room. Some of it does and some of it doesn't, depending on how the employer characterizes each item. She funds the full IRA amount in May, then learns in February that part of it was an excess contribution earning a repeating penalty.
A man stops working at the end of a year in which he maxed both Roth buckets. The following year his taxable income is the lowest it will ever be — an ideal window for converting pre-tax money at a low rate. He has no cash left to pay the conversion tax, because it went into the Roth IRA the year before at a much higher marginal rate.
Frequently Asked Questions
No. They are separate limits under separate rules, and funding one to the maximum leaves the other untouched. What can reduce your Roth IRA contribution is your income relative to the phase-out range, or having less earned compensation for the year than the contribution amount. Confirm the current limits and income ranges with the IRS for the year in question.
Yes, the catch-up amounts are separate — one applies inside the employer plan and one applies to IRAs. The plan-side catch-up now depends on your age band and, for higher-wage participants, may be required to be made on a Roth basis. Effective dates and amounts for those provisions have shifted, so verify the current rules with the IRS and confirm your plan actually offers the feature.
There is a correction path: remove the contribution with its attributable earnings by the applicable deadline, or recharacterize it as a traditional IRA contribution. If nothing is corrected, an excess contribution carries a penalty that repeats each year it remains. The deadlines are specific, so confirm them against current IRS guidance rather than waiting for someone to notify you.
That depends on facts specific to you — your marginal rate this year, your expected rate in retirement, and how much accessible cash you will need before other income sources start. Roth dollars from contributions and Roth dollars from later conversions cost different amounts of tax, and money spent on one is not available for the other. The decision involves comparing those two prices, not just checking eligibility.
No. Employer contributions sit inside the plan and count toward the plan's overall annual addition cap, not your IRA limit. Whether a match can be made on a Roth basis depends on the plan's features and current rules, which is a question for your plan administrator.