Up to $47,500 a year into a Roth sounds like a free win, until you move to India. A mega backdoor Roth is still legal today, but it only pays off if you stay in the US long enough. Here are the limits, the plan features you need, and when to skip it.
How the after-tax 401(k) route works
Your 401(k) has a total yearly limit under Section 415(c) of $72,000 if you're under 50. Your own deferral uses $24,500 of it, and any employer match or profit sharing uses more. What remains is your after-tax room, based on the IRS's 2026 limits.
The room you have
Priya is 34, defers the full $24,500, and her employer adds a $6,000 match. Her 2026 room works out like this.
Worked example, 2026
- Total 401(k) limit under Section 415(c): $72,000
- Her own deferral: minus $24,500
- Employer match: minus $6,000
- Her after-tax room: $41,500
With no employer money at all, the ceiling is $47,500.
What your plan must allow
The strategy lives or dies on your plan document, and a verbal yes from HR isn't enough. Check your Summary Plan Description for two features:
- After-tax contributions, which are a separate bucket from Roth deferrals.
- An in-plan Roth conversion or an in-service withdrawal, so you can move the money while you still work there.
A plan with the first feature but not the second traps your after-tax money until you leave the employer. Highly paid employees can also be refunded contributions if the plan fails its nondiscrimination test, which unwinds the benefit.
Convert fast, or the earnings get taxed
Your contributions were already taxed, so converting them costs nothing. Earnings that build up before you convert are taxed as ordinary income. That's why a plan that converts automatically after each paycheck works best.
How moving to India changes the math
Why the tax-free label stops at the border
India has no tax-free retirement wrapper and no CBDT ruling on how a US Roth should be treated. A common misconception is that the tax-free status moves with you. What decides your bill is your residency stage.
- While you're RNOR or a non-resident, a Roth withdrawal paid into a US account and kept abroad isn't taxed in India.
- Once you're ROR, I report the growth at your Indian slab rate and treat your contributions as a return of capital. The US collected no tax on the growth, so there's nothing to credit against it.
The full India-side rules for Roth withdrawals are in the IRA guide for NRIs.
The RNOR window is shorter than the five-year clocks
RNOR often lasts two to three Indian financial years, and the RNOR window is the one stretch where foreign income received abroad stays outside India's tax net.
Each Roth conversion starts its own five-year clock. Converted money taken out before 59½ can draw the 10% additional tax inside that period. Annual conversions stack clocks that all outlast your RNOR window.
RNOR doesn't make a Roth withdrawal free, either. It covers India only, so the US still taxes earnings on a non-qualified withdrawal and can add the 10% additional tax before 59½.
When a mega backdoor Roth still makes sense before you move
This applies to US-based workers with a 401(k) who expect to return. If you're a US citizen or green card holder, the US side of your Roth doesn't change when you move. Only the India side changes.
It's a good fit when all three of these hold:
- You'll stay in the US five more years or longer, or your move date is uncertain.
- You already take the full employer match and max your regular deferral.
- Your plan converts automatically, and you won't need the cash soon.
It's a poor fit if you'll leave within about two years and retire in India as ROR. I'd skip it there. The money sits behind five-year clocks, and the growth may meet Indian tax with no credit.
What to do before you move
- Read your Summary Plan Description for after-tax contributions and in-plan conversions or in-service withdrawals.
- Take the full match and max your regular deferral first. If your employer offers no match, read whether to contribute anyway before you decide which account to max out.
- Sort your timeline: five years out or more, run it. Under two years, skip it. In between, have a cross-border CPA model both countries, because your citizenship and how long you'll be ROR change the answer.
- Convert after every paycheck, and keep your contribution records permanently. India has no guidance on the principal-versus-growth split, so those records are your proof.
- Before you leave, settle your 401(k) withdrawal strategy and whether to roll over the 401(k), so the big moves land inside your RNOR window. The same window also helps with cost basis on US stocks.
Your next step
Request your plan's Summary Plan Description this week and check it for the two features above. If you're leaving within two years, I'd skip the after-tax contributions and keep that cash flexible. If your move date is still open, InvestMates can model both countries for you.
Frequently asked questions
Is mega backdoor Roth still allowed today?
Yes, the after-tax 401(k) conversion strategy is still allowed today, under the 2026 limits of $72,000 total and $24,500 deferral. Your employer can add or drop the plan feature, so check the current document. After the move, Roth withdrawals are taxed in India under a separate set of rules.
Who is eligible for mega backdoor Roth?
Anyone whose 401(k) plan allows after-tax contributions plus in-plan Roth conversions or in-service withdrawals, and there's no income limit. Your room is $72,000 minus your deferral and any employer money. Nondiscrimination testing can still refund contributions for highly paid employees.
Is a mega backdoor better than a backdoor Roth IRA?
Neither is better, because they do different jobs. A backdoor Roth IRA caps at $7,500 in 2026, and the pro-rata rule taxes part of the conversion if you hold pre-tax IRA money. The after-tax 401(k) route has up to $47,500 of room and no pro-rata rule, but it needs plan support.
What is the 5-year rule for Roth conversions from an after-tax 401(k)?
Two five-year clocks apply once converted money sits in a Roth IRA. One starts on January 1 of the first year you fund any Roth IRA and decides when earnings come out tax free. The other starts separately for each conversion and decides whether converted money taken out before 59½ draws the 10% additional tax.
Is there a downside to the after-tax 401(k) route if you're moving to India?
Yes, India may tax a Roth's growth once you're ordinarily resident, with no US tax to credit against it. Converted money also sits behind five-year clocks. Check how RNOR status applies to you before you commit.