For a high earner who already maxes their 401(k), is a backdoor Roth IRA worth the complexity now, and which brokerage is best for it?

Yes, a backdoor Roth IRA is definitely worth the complexity for high earners who already max out their 401(k), as it unlocks decades of tax-free growth and tax-free withdrawals in retirement where no other direct vehicle exists.

Is It Worth the Complexity?

• Tax-Free Growth: Unlike a traditional pre-tax account, Roth withdrawals do not trigger taxes or required minimum distributions (RMDs) during your lifetime.
• Low Actual Complexity: A standard backdoor Roth IRA (nondeductible Traditional IRA contribution followed by an immediate Roth conversion) only requires filling out IRS Form 8606 at tax time.
• The Pro-Rata Catch: It is only complex or punitive if you have pre-existing balances in traditional, SEP, or SIMPLE IRAs, which trigger the IRS pro-rata rule (making part of your conversion taxable). If your pre-tax money lives safely inside a current employer's 401(k), execution takes just a few clicks.

Best Brokerages for a Backdoor Roth IRA

The best brokerages feature zero account fees, robust customer service to handle transfers smoothly, and wide selections of low-cost index funds.

To help tailor this, let me know:

• Do you currently have any pre-tax balances in traditional or rollover IRAs?
• Are you looking into a standard backdoor IRA ($7,000/$7,500 limit) or a Mega Backdoor Roth through your employer's 401(k)?

Yes—for a high earner who already maxes a 401(k), a backdoor Roth IRA is usually worth doing, provided you don't have a large pre-tax traditional/SEP/SIMPLE IRA balance creating a pro-rata tax issue.

Why it’s attractive

For 2026, the IRA contribution limit is $7,500, or $8,600 if you're 50+.

If your income is too high for a direct Roth contribution—the 2026 Roth phaseout is $153k–$168k for single filers and $242k–$252k for married filing jointly—you can generally:

1. Contribute after-tax money to a traditional IRA.
2. Convert that contribution to a Roth IRA.
3. Invest it in the Roth.
4. Repeat annually.

The major benefit is that future investment growth can be tax-free, giving you another tax-advantaged bucket beyond the 401(k).

The big catch: the pro-rata rule

This is the part that determines whether I'd recommend it.

If you have pre-tax money in traditional, SEP, or SIMPLE IRAs, the IRS generally doesn't let you say, "I'm converting only the after-tax $7,500." Instead, the conversion is generally prorated between your pre-tax and after-tax IRA money.

For example, if you have:

• $93,000 of pre-tax IRA money
• $7,000 of nondeductible contribution

then only about 7% of a conversion is treated as after-tax. The rest can be taxable.

So if you have $0 of pre-tax IRA balances, the backdoor Roth is relatively straightforward. If you have substantial pre-tax IRA assets, I'd pause and look at alternatives—often rolling that IRA into your current 401(k), if the plan accepts roll-ins, can eliminate the problem.

Which brokerage?

My default pick would be Fidelity.

| Fidelity | Schwab | Vanguard --- | --- | --- | --- IRA account fee | $0 | $0 | Generally low/no cost depending on account/holding Online stock/ETF commissions | $0 | $0 | $0 Fractional shares | Excellent | Good | More limited Ease of backdoor Roth | Excellent | Excellent | Good Overall pick | 🥇 | 🥈 | 🥉

Fidelity currently offers IRAs with no account-opening fees or minimums, and its brokerage supports a broad range of investments. Fidelity Fidelity Schwab likewise lists $0 opening and maintenance fees and $0 online stock/ETF commissions. Schwab Brokerage Vanguard also has $0 online stock/ETF commissions.

Why I lean Fidelity: for a simple backdoor Roth, you don't need fancy features—you want a clean traditional IRA → Roth IRA workflow, inexpensive index funds/ETFs, easy fractional investing, and good automation. Fidelity checks those boxes particularly well.

My rule of thumb

If you're a high earner and:

• ✅ Already maxing your 401(k)
• ✅ Have no meaningful pre-tax traditional/SEP/SIMPLE IRA balances
• ✅ Have at least ~$7,500 of additional money you'd otherwise invest in taxable
• ✅ Expect to leave the money invested for years

I'd probably do the backdoor Roth every year.

It's one of those strategies where the administrative complexity is mostly front-loaded. Once the accounts are established, the annual process is fairly mechanical.

One important detail: don't accidentally leave the converted money sitting in the traditional IRA earning interest before converting it. Ideally, contribute the cash and convert it promptly. Any earnings that accrue before conversion can create a small taxable amount.

If you tell me (1) your filing status, (2) approximate income, (3) whether you have any traditional/SEP/SIMPLE IRA balances, and (4) your age, I can tell you whether I'd personally do the backdoor Roth in your situation and lay out the exact steps.

My default pick would be Fidelity.

| Fidelity | Schwab | Vanguard --- | --- | --- | --- IRA account fee | $0 | $0 | Generally low/no cost depending on account/holding Online stock/ETF commissions | $0 | $0 | $0 Fractional shares | Excellent | Good | More limited Ease of backdoor Roth | Excellent | Excellent | Good Overall pick | 🥇 | 🥈 | 🥉

Yes—for a high earner who already maxes a 401(k), I’d generally do a backdoor Roth IRA if you can do it cleanly. The complexity is modest, and the main benefit is getting another bucket of money into a tax-free retirement account.

Why it’s usually worth it

For 2026, the IRA contribution limit is $7,500, or $8,600 if you're 50+. Direct Roth contributions phase out at higher incomes—$153k–$168k for single filers and $242k–$252k for married filing jointly—so a high earner may need the backdoor approach.

The basic process is:

1. Contribute $7,500 of after-tax money to a Traditional IRA.
2. Convert that amount to a Roth IRA.
3. Invest it in the Roth.
4. Repeat annually.

The attraction is that future qualified withdrawals are tax-free, and you're building an asset that isn't subject to future ordinary-income tax rates.

The big catch: the pro-rata rule

This is the part I'd check before opening the account.

If you have pre-tax money in Traditional, SEP, or SIMPLE IRAs, you generally can't simply declare the $7,500 conversion tax-free. The IRS looks at your IRA balances in aggregate when determining the taxable portion.

Example: If you have $92,500 of pre-tax IRA money and add $7,500 after-tax, only about 7.5% of a $7,500 conversion would represent after-tax money. Most of the conversion would be taxable.

If you don't have pre-tax IRA balances, the backdoor Roth is usually extremely clean: contribute $7,500, convert it shortly thereafter, and there's little or no taxable gain to worry about.

One potentially useful workaround: if your 401(k) permits it, you may be able to roll an existing pre-tax IRA into the 401(k), leaving your IRAs effectively empty before doing the backdoor Roth. The specific plan has to accept the rollover.

Which brokerage?

My pick for this specific use case is Fidelity.

| Fidelity | Schwab | Vanguard --- | --- | --- | --- IRA account fees | $0 | $0 | $0 to open Roth conversion fee | $0 | $0 | Generally none Ease of backdoor Roth | Excellent | Excellent | Good Fractional ETF investing | Excellent | Good | Good Overall pick | 🥇 | 🥈 | 🥉

Fidelity explicitly lists $0 for Roth conversions, and its retail IRAs have no account fees or minimums.

Schwab is essentially just as viable: it charges no fee to open or maintain an IRA and offers $0 online stock/ETF trades.

Vanguard is also perfectly reasonable, particularly if you're already heavily invested in Vanguard funds, although I find Fidelity's overall account experience better for this particular "contribute → convert → invest" workflow. Vanguard says there's no charge to open an IRA.

My rule of thumb

If you're in this situation:

High income + maxed 401(k) + no pre-tax Traditional/SEP/SIMPLE IRA balance + long investment horizon I'd consider the backdoor Roth almost a no-brainer. The extra paperwork once a year is tiny compared with the potential value of another $7,500/year compounding tax-free.

And I'd use Fidelity + a simple low-cost index-fund portfolio.

One important distinction: a backdoor Roth is not an additional $7,500 on top of the IRA limit. It is simply a method of getting your otherwise-ineligible Roth contribution into the Roth.

If you tell me your age, approximate income, filing status, and whether you have any Traditional/SEP/SIMPLE IRA balances, I can show you exactly how I'd execute the backdoor Roth and what the tax consequences would look like for you.

Is a Backdoor Roth IRA Worth It?

For a high earner who already maxes out a 401(k), the short answer is yes, it is almost always worth the complexity.

• Tax-Free Growth: The annual contribution limit is $7,500 (or $8,600 if you are 50 or older). While it feels small compared to a $23,000+ 401(k), decades of tax-free compounding on that money results in a massive pool of completely tax-free cash in retirement.
• Tax Diversification: Having tax-free buckets (Roth) alongside tax-deferred buckets (Traditional 401k) gives you flexibility in retirement to manage your tax bracket and control your required minimum distributions (RMDs).
• The Only Caveat (The Pro-Rata Rule): It is only "not worth it" if you currently hold significant pre-tax money in a Traditional, Rollover, SEP, or SIMPLE IRA. If you have pre-tax IRA balances, the IRS applies the dreaded pro-rata rule , making part of your conversion taxable. If your only pre-tax money is safely locked inside an employer 401(k), you can bypass this easily, making the process clean.

Which Brokerage is Best for It?

The "best" brokerage is one that handles non-deductible contributions, partial transfers, and year-end reporting seamlessly without forcing you onto paper forms or charging hidden fees.

• Fidelity Investments
  • Why it’s great: Fidelity Investments is widely considered a top choice. Moving money from a Traditional IRA to a Roth IRA can be initiated entirely online with a few clicks, and their customer service reps are exceptionally well-versed in walking people through the mechanics if you hit a snag. They also have great zero-fee index funds.
• Charles Schwab
  • Why it’s great: Charles Schwab offers robust online transfer tools and an intuitive interface for managing multi-leg transfers between a Traditional and Roth IRA. Customer support is easily reachable by phone to finalize or troubleshoot conversions.
• Vanguard
  • Why it’s great: Vanguard is built for the buy-and-hold passive investor. While their platform interface feels a bit dated compared to competitors, the actual online wizard for executing a Roth conversion from a Traditional IRA is straightforward and reliable.

(Note: Avoid brokerages that force you to print, sign, and mail physical forms or call a representative just to complete the conversion step.)

To help narrow down your setup, let me know:

• Do you currently have any pre-tax balances in a Rollover or Traditional IRA from a past job?
• Are you looking for specific investment options (like index funds or individual stocks) inside the account?

For a high earner who is already maxing out a 401(k), a backdoor Roth IRA is widely considered worth the effort , provided you don't run afoul of the pro-rata rule.

Is It Worth the Complexity?

• The Math: The annual contribution limit is $7,500 (plus $1,100 if you're 50 or older). While it feels small compared to a 401(k), decades of tax-free compounding on that principal amount yield massive tax-free pools of money in retirement.
• The "Complexity" Reality: It isn't actually complex day-to-day—it boils down to making a non-deductible contribution to a Traditional IRA and then immediately converting it to a Roth IRA.
• The Catch (The Pro-Rata Rule): It is only a headache if you have pre-tax money sitting in any Traditional, Rollover, SEP, or SIMPLE IRA. If you do, the IRS forces a pro-rata calculation on conversions, meaning a chunk of your conversion becomes taxable. If you have a zero balance across all traditional IRAs (often by reverse-rolling old IRAs into a current employer 401k), it takes about 10 minutes a year plus Form 8606 at tax time.

Which Brokerage is Best?

Any major low-cost brokerage can handle the mechanics, but a few stand out depending on your priorities:

• Fidelity Investments: Widely regarded as one of the best overall choices. Moving money between a Traditional IRA and a Roth IRA is seamless, cash sweeps quickly, and customer service is reachable if you need reassurance on the transfer steps. They also offer zero-expense ratio index funds if you want to keep costs at absolute zero.
• The Vanguard Group: Excellent for long-term buy-and-hold investors utilizing low-cost index funds or ETFs. Their platform handles non-deductible contributions and conversions cleanly, though the interface is more utilitarian.
• Charles Schwab: Highly reliable with top-tier customer support and a robust platform, making transfers between traditional and Roth structures straightforward.
• Robinhood: Surprisingly competitive if you subscribe to Robinhood Gold, as they offer a match on IRA contributions (up to 3% with Gold). For a high earner looking to maximize every absolute dollar, an extra boost on the annual contribution can tip the scales—just ensure you understand their holding period rules for the match.

Do you currently have any pre-tax balances in traditional, rollover, or SEP IRAs , or is your IRA balance currently zero?

Yes—for a high earner who already maxes a 401(k), I’d generally consider a backdoor Roth IRA worth doing, provided you don't have a large pre-tax traditional/SEP/SIMPLE IRA balance creating a pro-rata tax problem.

Why it’s attractive

For 2026, the IRA contribution limit is $7,500 ($8,600 if age 50+). Direct Roth contributions phase out at $153k–$168k of MAGI for single filers and $242k–$252k for married filing jointly. Above those ranges, the backdoor Roth is a common way to get the same $7,500 into a Roth.

The basic sequence is:

1. Contribute $7,500 of after-tax cash to a traditional IRA.
2. Convert that contribution to a Roth IRA.
3. File IRS Form 8606 to document the nondeductible contribution.
4. Invest the money in the Roth.

If the conversion happens promptly, there's usually little or no taxable income because you're converting money that was already contributed after tax. Any investment gains between contribution and conversion can be taxable.

The big benefit is that the Roth then provides tax-free qualified withdrawals, tax-free growth, and no lifetime RMDs.

The one issue I'd check first

Do you have any traditional, SEP, or SIMPLE IRAs with pre-tax money?

This is the main complication. The IRS's pro-rata/aggregation rules effectively look across your traditional IRAs when determining how much of a Roth conversion is taxable. You can't simply say, "I'll convert only the $7,500 after-tax contribution."

For example, if you have:

• $90,000 of pre-tax traditional IRA money
• $10,000 of nondeductible basis

and you convert $10,000, roughly 90% of that conversion would generally be taxable—not zero.

If you don't have pre-tax IRA balances, the strategy is remarkably clean.

Which brokerage?

My pick for most people: Fidelity Investments.

I'd rank the major choices:

Fidelity has $0 account fees, no minimums on its mutual funds, and $0 online stock/ETF commissions.

Schwab is similarly compelling: $0 to open/maintain an IRA, $0 minimum, $0 online listed-equity commissions, and strong customer support.

Vanguard remains excellent for low-cost investing, though its brokerage/service structure is somewhat less compelling to me for a simple backdoor-Roth workflow. Vanguard currently lists $0 online stock/ETF commissions.

My practical recommendation

If you're a high earner and already maxing the 401(k), I'd think about your priority order as:

401(k) → backdoor Roth → HSA (if eligible) → taxable brokerage, subject to your specific tax situation and employer plan.

The backdoor Roth is especially attractive because you're effectively buying another bucket of tax-free future growth each year. $7,500/year compounded for 25 years at 7% would grow to roughly $475,000, and qualified Roth withdrawals wouldn't be subject to federal income tax.

The complexity is mostly one annual administrative task. For someone earning substantially above the Roth income limit, I don't think that complexity is enough reason to skip it.

One caveat: if you have existing pre-tax IRA money, tell me roughly how much and whether you're single or married filing jointly. That can completely change whether I'd recommend doing the backdoor Roth—and there may be a clean way to eliminate the pro-rata problem through your 401(k).

Yes—for a high earner who already maxes the 401(k), a backdoor Roth is usually worth doing, provided you don't have significant pre-tax IRA balances that trigger the pro-rata rule.

Why I'd generally do it

For 2026, you can put $7,500 into an IRA through the backdoor ($8,600 if age 50+).

The basic sequence is:

1. Contribute $7,500 of after-tax money to a Traditional IRA.
2. Convert that contribution to a Roth IRA.
3. Invest the money in the Roth.
4. File IRS Form 8606 to document the nondeductible contribution.

The real attraction isn't the immediate tax deduction—you don't get one. It's getting another pool of money into an account where future qualified growth and withdrawals can be tax-free, and Roth IRAs don't have lifetime RMDs for the original owner.

For someone already maxing their 401(k), I view $7,500/year of additional Roth space as pretty valuable for relatively little administrative hassle.

The big catch: the pro-rata rule

This is the thing I'd check before doing it.

If you have, say:

• $100k in a rollover IRA
• $20k in a Traditional IRA
• $7,500 new nondeductible contribution

you generally can't tell the IRS "I'm only converting the $7,500." Your Traditional/SEP/SIMPLE IRA balances are aggregated for the tax calculation, so part of the conversion would generally be taxable.

If you have $0 of pre-tax IRA money, the backdoor is exceptionally clean: contribute $7,500, convert it promptly, and there's usually little or no taxable income from the conversion.

One useful workaround if you have an old rollover IRA is sometimes to move that pre-tax IRA money into your current employer's 401(k), if the plan accepts roll-ins. That can potentially clear the way for a clean backdoor Roth.

Which brokerage?

My default choice would be Fidelity.

Fidelity: The process is straightforward, there's no account fee, and you get an enormous selection of low-cost investments. Fidelity also explicitly supports the backdoor Roth workflow.

Schwab: Also excellent. Schwab currently charges $0 to open and maintain an IRA, with $0 online commissions for stocks and ETFs.

I wouldn't choose based on a tiny difference in trading costs. For a backdoor Roth, ease of contribution → conversion → tax reporting matters more.

One thing I'd investigate before doing the backdoor

Since you're already maxing the 401(k), check whether your employer's plan supports a mega backdoor Roth.

That's potentially much more valuable. In 2026, the overall 401(k) contribution limit is $72,000 for someone under 50, including employee contributions, employer contributions, and qualifying after-tax contributions. A plan that permits after-tax contributions plus in-plan Roth conversions or in-service rollovers can potentially let you put tens of thousands more into Roth space than the $7,500 regular backdoor Roth.

So my priority order for a high earner would generally be:

401(k) match → max 401(k) → HSA if eligible → mega backdoor Roth if available → regular backdoor Roth → taxable brokerage.

If you tell me your approximate income, age, filing status, and whether you have any Traditional/SEP/SIMPLE/rollover IRA balances, I can tell you whether the backdoor Roth is actually advantageous in your situation and show the tax mechanics with numbers.

For a high earner who has already maxed out a 401(k), executing a backdoor Roth IRA is almost universally worth the complexity.[1]

Why It’s Still Worth It

• Tax-Free Growth & Withdrawals: The standard Roth IRA contribution limit is $7,500 (with an extra $1,100 catch-up if you're 50+). Compounded over decades, getting an extra $7,500 a year into an account where growth and withdrawals are completely tax-free translates to a massive pool of untaxed wealth in retirement. [1][2][3][4]
• No RMDs: Roth IRAs do not have Required Minimum Distributions (RMDs) during your lifetime, giving you elite tax flexibility in your later years.[1][2]
• The "Complexity" is Overstated: Once you do it the first time, it takes about 15 minutes a year. The only real trap is the Pro-Rata Rule —if you have existing pre-tax money in any Traditional, Rollover, SEP, or SIMPLE IRA, the conversion will trigger a pro-rata tax hit. If you have zero pre-tax IRA balances (or can reverse-rollover them into your current employer's 401(k)), it is frictionless.[1][2][3][4][5]
• Filing Form 8606: You just have to remember to file IRS Form 8606 with your taxes to report the non-deductible Traditional IRA contribution and subsequent conversion. Your CPA or tax software handles this easily. [1][2][3][4][5]

Which Brokerage is Best?

The best brokerages for a backdoor Roth IRA are institutions that handle the transfer cleanly, charge $0 fees, and have customer service reps who actually know what a non-deductible-to-Roth conversion is.

- **Why it's great:** Fidelity is widely considered the gold standard for executing this smoothly. Their platform makes opening a Traditional IRA and a Roth IRA seamless, moving cash between them takes seconds online, and their phone support understands the mechanics immediately if you hit a snag. They also offer an immense array of zero-fee or low-cost index funds.[1][2][3]

- **Why it's great:** Vanguard pioneered low-cost investing and handles the mechanics reliably. While their user interface feels a bit more utilitarian and old-school, they are rock-solid for long-term buy-and-hold retirement investors.[1][2]

- **Why it's great:** Following their integration of TD Ameritrade, Schwab offers a robust platform and great customer service. Executing the two-step dance (contribute to Traditional, convert to Roth) is straightforward on their web portal.[1][2]

To help narrow this down, let me know:

• Do you currently have any pre-tax balances in a Rollover, Traditional, or SEP IRA?
• Which brokerage do you currently use for your other investments or 401(k)?

Yes—for a high earner who already maxes the 401(k), a backdoor Roth is usually worth doing, provided you don't have a large pre-tax IRA balance that triggers an unpleasant tax bill under the pro-rata rule.

Why it’s attractive

In 2026, the IRA contribution limit is $7,500 ($8,600 if 50+), while the 401(k) employee deferral limit is $24,500. High earners generally can't contribute directly to a Roth IRA once their income is above the applicable limits.

The backdoor strategy is essentially:

1. Contribute $7,500 of after-tax money to a Traditional IRA.
2. Convert that amount to a Roth IRA.
3. Invest it inside the Roth.
4. Repeat annually.

The big benefit is that future investment growth can be tax-free, and Roth IRAs don't have lifetime RMDs for the original owner. For someone with decades of compounding ahead, that extra tax-free bucket can be quite valuable.

The big catch: the pro-rata rule

This is the part I'd check before doing it.

If you have, for example:

• $100,000 in a traditional IRA
• $7,500 new nondeductible contribution
• $0 in Roth IRAs

you generally can't simply declare the $7,500 conversion tax-free. The IRS looks at your IRA balances collectively when determining the taxable portion of the conversion.

If you have no pre-tax Traditional/SEP/SIMPLE IRA money, the backdoor Roth is particularly clean: contribute $7,500, convert it, and generally owe little or no tax if the conversion happens promptly before significant earnings accrue.

One important planning trick: a pre-tax IRA can sometimes be rolled into your current employer's 401(k) if the plan accepts roll-ins. That can potentially clear the way for future backdoor Roths.

Which brokerage?

My default pick would be Fidelity.

fidelity.com offers $0 account fees/minimums for its IRAs and lets you invest with as little as $1.

I'd rank them roughly:

schwab.com also has $0 IRA opening/maintenance fees and $0 minimums.

investor.vanguard.com remains an excellent low-cost investment provider, and its online stock/ETF commissions are $0, but its current account-fee structure is a little less attractive than Fidelity's for a straightforward IRA setup.

My practical recommendation

If you're a high earner, already maxing your 401(k), and don't have pre-tax IRA balances, I'd probably do the backdoor Roth every year.

At $7,500/year, you're not going to transform your retirement overnight—but over 20–30 years, you're creating a potentially substantial pool of tax-free assets. The administrative hassle is fairly small once the accounts are established.

If you tell me (1) your approximate age, (2) filing status, (3) whether you have any Traditional/SEP/SIMPLE IRA balances, and (4) whether your 401(k) accepts after-tax rollovers, I can tell you whether I'd do the backdoor Roth in your particular situation and whether there are better options beyond it.

For a high earner who has already maxed out a 401(k), the short answer is yes, a backdoor Roth IRA is almost always worth it , provided you don't run afoul of the pro-rata rule.

The complexity is largely a one-time learning curve. Once you've done it once or twice, it takes about 10 minutes a year, and the long-term tax-free compounding on that capital is massive.

Is it worth the complexity?

• The Math: You get to funnel after-dollar savings ($7,500 for 2026, or $8,600 if you’re 50+) into a vehicle where it grows 100% tax-free forever. In retirement, withdrawals don't trigger taxes or push up your taxable income.
• The Caveat (The Pro-Rata Rule): It is only "complex" or painful if you currently have pre-tax money sitting in any Traditional, Rollover, SEP, or SIMPLE IRAs. If you do, the IRS forces you to pro-rate the conversion, meaning a chunk of it will be unpleasantly taxed. If your only pre-tax buckets are your 401(k)/403(b), you are completely in the clear to do a clean backdoor Roth.
• The Paperwork: It requires filing IRS Form 8606 with your annual tax return to document the non-deductible Traditional IRA contribution. Any good tax software (TurboTax, FreeTaxUSA, CPA) handles this effortlessly if you check the right boxes.

Which brokerage is best for it?

The major low-cost brokerages handle this well, but some make the user interface significantly smoother than others:

• • Fidelity: Widely considered a top choice by the Bogleheads community on Reddit and The Money Guy Show community , Fidelity has ultra-fast electronic bank transfers, allows you to hold the traditional IRA contribution in a core money market fund instantly, and makes moving the money to your Roth IRA via internal transfer or conversion prompt seamless.
• • Vanguard: Historically a pioneer for low-cost investing, Vanguard features a dedicated, streamlined online conversion tool directly in the interface that lets you complete the transfer step with minimal clicks.
• • Charles Schwab: Very reliable with great customer service, though moving external funds can sometimes take a couple of business days to settle before you safely convert.

The Verdict: Fidelity or Vanguard edge out the competition for sheer speed and friction-free UI when executing the two-step dance.

Do you currently have any rollover or traditional IRAs from past jobs, or is your pre-tax money strictly inside your current 401(k) ? I can help you figure out if the pro-rata rule will affect you.