The Backdoor Roth and Mega Backdoor Roth: A Guide for High Earners Locked Out of Direct Roth Contributions

If your income is high enough, the IRS won't let you contribute to a Roth IRA directly. For 2026, once modified adjusted gross income crosses roughly $165,000 for single filers or $246,000 for married couples filing jointly, the door closes. That rule catches a lot of successful professionals off guard, especially the ones who assumed tax-free growth was something they'd earned the right to.

Here's the good news: there's a legal, well-established path around that limit. Two of them, actually, and they apply to different accounts.

Curious whether either strategy fits your situation? Schedule a complimentary consultation with Ben Loughery.

The Backdoor Roth IRA

The backdoor Roth isn't a loophole in the sense of something clever or gray-area. It's a two-step process that's been standard practice for over a decade.

• Contribute to a traditional IRA (no income limit applies to this step).
• Convert that traditional IRA balance to a Roth IRA shortly after.

Because the contribution was made with after-tax dollars, the conversion typically triggers little to no additional tax — assuming you don't already hold other pre-tax IRA money.

That last clause deserves more attention than it usually gets. If you have existing traditional, SEP, or SIMPLE IRA balances, the IRS applies something called the pro-rata rule. It treats all your IRA dollars as one pool for tax purposes, so a portion of every conversion gets taxed based on the ratio of pre-tax to after-tax money across all your IRAs combined. A client with $200,000 sitting in a rollover IRA from an old employer plan can't simply convert a fresh $7,000 contribution and call it tax-free — the pro-rata calculation will pull in a slice of that pre-tax balance too.

Who this fits: High earners who don't hold significant traditional IRA balances, or who are willing to roll existing IRA money into a 401(k) first to clear the pro-rata problem before converting.

The Mega Backdoor Roth

This version lives inside your 401(k), and it can move far larger amounts — sometimes $30,000 to $40,000 a year, depending on your plan's design.

Here's the mechanism. Total 401(k) contributions — yours, your employer's match, and profit-sharing combined — are capped at $72,000 for 2026 (higher with catch-up contributions if you're 50 or older). Most people never get close to that ceiling with regular pre-tax or Roth deferrals alone. The gap between what you and your employer contribute and that overall cap is where after-tax contributions come in.

If your plan allows after-tax contributions on top of the standard deferral limit, and it allows in-service withdrawals or automatic in-plan Roth conversions, you can push extra dollars into the account after-tax and then convert them to Roth, either inside the plan or by rolling them into a Roth IRA. Done correctly and quickly, the conversion carries minimal tax because there's been little time for growth to accumulate.

The catch: not every 401(k) plan allows this. It depends entirely on plan design — specifically whether after-tax contributions and in-service distributions or automatic conversions are built into the plan document. Some large employers offer this feature; many small business 401(k)s don't.

What to Check Before You Try Either Strategy

• Do you already hold pre-tax IRA balances that would trigger the pro-rata rule?
• Does your 401(k) plan document permit after-tax contributions above the standard deferral limit?
• Does the plan allow in-service withdrawals or automatic Roth conversions of those after-tax dollars?
• How quickly does your plan process conversions — delays can mean unwanted taxable growth?
• Are you contributing consistently enough to make the paperwork worth the tax benefit?

Why Bother With Any of This

Tax-free growth compounds without a tax bill waiting at the other end. For someone in their peak earning years with two or three decades until retirement, redirecting even $10,000 to $20,000 a year into Roth space instead of a taxable brokerage account can mean a meaningfully larger tax-free bucket by the time distributions start. It also gives you more flexibility later — Roth withdrawals don't count toward the income thresholds that trigger higher Medicare premiums or push more of your Social Security into taxable territory.

Is This Worth Setting Up for Your Situation?

The mechanics aren't complicated once you've done them, but the setup — checking plan documents, coordinating timing, avoiding the pro-rata trap — is where people trip. If you're a high earner wondering whether your employer's 401(k) even allows the mega backdoor version, that's a five-minute question your HR department or plan administrator can answer, and it's worth asking before assuming the strategy isn't available to you.

Schedule a complimentary consultation with Ben Loughery at Lock Wealth Management, and let's find out whether either version of this strategy belongs in your plan.

Ben Loughery is a CERTIFIED FINANCIAL PLANNER® and founder of Lock Wealth Management, based in Atlanta, GA. He specializes in retirement income planning, tax optimization, and helping clients build financial confidence at every stage of life.