What is a Backdoor Roth IRA?

The IRS imposes income limits on who can contribute directly to a Roth IRA. In 2024, if you are single and earn over $161,000 (or Married Filing Jointly and earn over $240,000), you are barred from making direct contributions. However, the "Backdoor Roth" strategy allows high earners to legally bypass these limits.

How the Backdoor Roth Works

The process involves two steps: First, you make a "non-deductible" contribution to a Traditional IRA. Unlike direct Roth contributions, there are no income limits for contributing to a Traditional IRA (though your income dictates whether you can deduct it from your taxes). Second, you immediately convert that Traditional IRA balance into a Roth IRA. Because you already paid taxes on the initial non-deductible contribution, the conversion is tax-free.

The Pro-Rata Rule Trap

The biggest pitfall of the Backdoor Roth strategy is the IRS Pro-Rata rule. When you execute a Roth conversion, the IRS looks at the aggregate total of all your Traditional, SEP, and SIMPLE IRAs across all brokerages as of December 31st of that year. You are not allowed to choose to only convert your "after-tax" money.

If you have $93,000 of old pre-tax 401(k) money rolled into a Traditional IRA, and you make a new $7,000 non-deductible contribution, your total IRA balance is $100,000. That balance is 93% pre-tax and 7% after-tax. When you convert $7,000 to a Roth IRA, the IRS dictates that the conversion must also be 93% taxable and 7% tax-free. You will owe income tax on 93% of the converted amount, defeating the purpose of the strategy.

How to Avoid the Pro-Rata Rule

To successfully execute a tax-free backdoor Roth conversion, your total pre-tax IRA balance on December 31st must be $0. The most common way to achieve this is to do a "reverse rollover," where you roll all your existing pre-tax Traditional IRA balances into your current employer's active 401(k) plan. 401(k) balances are completely ignored by the pro-rata rule calculation.

Important Deadlines

While you can make prior-year IRA contributions up until Tax Day (usually April 15th), a Roth conversion is strictly tied to the calendar year it is performed in. Furthermore, the IRS checks your Traditional IRA balance for the pro-rata calculation on December 31st of the year the conversion takes place.