How the Backdoor Roth IRA Works

The backdoor Roth is a two-step process. You contribute to a traditional IRA (no deduction, since you’re over the income limit), then convert that balance to a Roth IRA. The IRS doesn’t cap your income for conversions — only for direct Roth contributions. So the “backdoor” is really just a conversion that anyone can do, regardless of income.

The contribution itself isn’t taxable because you already used after-tax dollars. But if you have other traditional IRA balances — from old rollovers, SEP contributions, or deductible contributions in prior years — the pro-rata rule kicks in. The IRS treats all your traditional IRAs as one pool and taxes the conversion proportionally, per IRC Section 408(d)(2). A $7,000 backdoor contribution into an account with $93,000 of pre-tax money means roughly 93% of your conversion is taxable. That’s the part people miss.

The New York City Tax Layer

Most states have one income tax rate to worry about. NYC residents have two: the state rate and the city rate. At the top brackets, you’re looking at 10.9% to New York State plus 3.876% to the city. That’s 14.776% on top of whatever federal bracket you’re in.

For a backdoor Roth done cleanly — meaning no pre-tax IRA balances to trigger pro-rata — the tax hit is minimal. You contributed after-tax money, and the conversion of basis isn’t taxable. Any small earnings between contribution and conversion get taxed, but if you convert quickly (same week, ideally), that amount is negligible.

Where it gets expensive is if you have existing pre-tax IRA money. A large taxable conversion at NYC rates means you’re paying roughly 51.5% on the top slice when you add federal (37%), state (10.9%), and city (3.876%) together. That’s real money. You need to be confident the long-term tax-free growth justifies that upfront cost.

Why NYC Residents Planning to Leave Should Pay Attention

Here’s where the backdoor Roth gets especially interesting for New Yorkers. If you plan to move to a lower-tax or no-tax state — Florida, Texas, Tennessee, Nevada — converting money to Roth while you’re still in New York means you’re paying New York rates on the conversion. But the withdrawals in retirement? Tax-free everywhere, including your new state.

On the other hand, if you leave the money in a traditional IRA and move to Florida, you’d pay zero state tax on the withdrawals anyway. So the Roth conversion while in NYC only makes sense if you believe your federal rate in retirement will be higher than your federal rate now, or if you value the estate planning benefits of Roth accounts (no RMDs, tax-free inheritance).

For people staying in New York long-term, Roth conversions lock in tax-free growth that sidesteps future state and city taxes. If rates go up — which they have historically trended toward in New York — you’ve already paid at today’s rates.

Cleaning Up the Pro-Rata Problem

The cleanest backdoor Roth requires $0 in pre-tax traditional IRA balances on December 31 of the conversion year. If you have old rollover IRAs or SEP-IRA balances, you have a few options:

• Roll pre-tax IRA money into your employer’s 401(k) — most 401(k) plans accept incoming rollovers, and this clears the pro-rata issue entirely
• Convert everything at once — if the total balance is manageable, convert all pre-tax money to Roth in one year and take the tax hit; then future backdoor contributions are clean
• Do nothing and accept the partial taxation — some people just accept that each conversion will be partially taxable and spread it out over several years

There’s no single right answer. It depends on how much pre-tax IRA money you have, what bracket you’re in, and whether your employer plan allows rollovers. We walk clients through the specific numbers before recommending a path.

Timing and Practical Steps

The 2025 contribution limit for IRAs is $7,000 ($8,000 if you’re 50 or older). You can make the contribution and conversion at any time during the calendar year — or even contribute for the prior year up until the April filing deadline.

Most custodians (Fidelity, Schwab, Vanguard) make this a straightforward online process. Contribute to the traditional IRA, wait for the funds to settle (usually 1-3 business days), then request a Roth conversion. Don’t invest the traditional IRA contribution in anything volatile before converting — the point is to minimize gains between contribution and conversion.

One thing to watch: New York conforms to federal IRA rules, so there’s no special state form for the conversion. It flows through your federal return and carries onto your NY IT-201 and NYC return automatically.