If you earn too much to contribute to a Roth IRA directly, you've probably heard about the so-called backdoor Roth.
It's a legal workaround that lets high earners funnel money into a tax-free retirement account by contributing to a traditional IRA and then converting it.
For years, it's been a quiet favorite among six-figure earners who got shut out of regular Roth contributions.
But here's what rarely makes the headlines: the strategy comes with a tax trap that can bite you years later, and most people don't find out until it's too late.
If you hold any pre-tax money in a traditional IRA — from an old 401(k) rollover, for example — the IRS doesn't let you convert just your new after-tax contribution.
It looks at your total IRA balance and taxes the conversion proportionally.
That means a $7,000 backdoor contribution could trigger a tax bill on a chunk of your existing retirement savings.
Financial planners say this catches people off guard every tax season.
Someone contributes $7,000, converts it, and assumes they owe nothing.
Then their accountant runs the numbers and finds a surprise tax hit of several thousand dollars.
The fix is simpler than most people think.
If you have pre-tax money sitting in a traditional IRA, you can often roll it into your current employer's 401(k) before doing the conversion.
That clears out the pre-tax balance, so the pro-rata rule no longer applies.
Not every workplace plan accepts rollovers, so it's worth checking with your HR department first.
The IRS clarified that Roth conversions are not subject to required minimum distributions, and the agency has been steadily updating guidance on how the five-year rule applies to converted amounts.
Each conversion starts its own five-year clock for penalty-free withdrawal of the converted principal, though the account's overall five-year clock still governs earnings.
For 2026, the contribution limit for IRAs is expected to stay in the same range as 2025's $7,000, with a $1,000 catch-up for those 50 and older.
If you're married and both spouses qualify, that's up to $16,000 of tax-free growth potential per year — real money over a few decades.
The mechanics are straightforward once you've cleared the pre-tax hurdle.
You contribute to a traditional IRA, don't take a deduction, then convert the balance to a Roth.
You report both steps on Form 8606 when you file.
Miss that form and the IRS may assume the contribution was deductible, which creates a mess to untangle later.
One more thing: the strategy has survived repeated proposals to kill it.
Lawmakers have floated bans on backdoor conversions several times, most recently in broader retirement reform packages, but nothing has passed.
That doesn't mean it's permanent, though.
If you've been putting it off, the window may not stay open forever.
If you're unsure whether the pro-rata rule applies to you, a quick look at your traditional IRA balances is the place to start.
A tax professional can run the numbers before you convert, which is far cheaper than fixing a surprise bill in April.
The backdoor Roth isn't glamorous, and it isn't complicated once you understand the one rule that trips people up.
For high earners who've maxed out every other tax-advantaged option, it's still one of the better deals in the tax code.
Final Thoughts
Just clear out that pre-tax IRA first, or you'll be handing a chunk of your retirement to the IRS for no good reason.