Can I Do a Backdoor Roth IRA If I Already Have a Traditional IRA?

Can I do a backdoor Roth if I already have a traditional IRA?

Yes. Having a traditional IRA does not prevent a Roth conversion, but it can make part of the conversion taxable. The tax result depends on the total IRA picture, not only on the account that holds the new nondeductible contribution.

The IRS describes Form 8606 as the form for reporting nondeductible traditional IRA contributions and conversions from traditional IRAs to Roth IRAs. For the calculation, line 6 asks for the December 31 value of all traditional IRAs, plus outstanding rollovers. The instructions include traditional SEP and SIMPLE IRAs in the definition of traditional IRAs unless they say otherwise. See the IRS Instructions for Form 8606 for 2025.

This makes year-end timing matter. A conversion during the year does not let you ignore other included IRA money still present at year-end. A contribution made with after-tax dollars creates basis, but the form applies that basis to the taxpayer’s IRA activity under the calculation. It does not treat each account as a separate tax silo.

For context, the IRS set the 2025 IRA contribution limit at $7,000, or $8,000 for people age 50 or older, according to Publication 590-A for 2025. Those are contribution limits, not a promise that a conversion of the contribution will be tax-free. Contribution eligibility, deductibility, and conversion taxation are distinct questions.

Why is part of my backdoor Roth conversion taxable?

Part of the conversion is taxable when the total amount converted includes untaxed IRA money. The IRS says a Roth conversion results in taxation of untaxed amounts in the traditional IRA, and Form 8606 applies your after-tax basis to determine the taxable share.

Here is the arithmetic from Charles Schwab’s example. An IRA contains $400,000: $300,000 pre-tax and $100,000 after-tax. That makes three-quarters of the account pre-tax. If $100,000 is converted without first moving the pre-tax money, Schwab says 75% of the conversion is taxable. The example is specific to those balances; an individual’s result depends on their own basis, distributions, conversions, and year-end IRA values.

The central point is the denominator: the calculation considers the relevant pool of IRA assets, rather than letting someone select only after-tax dollars for conversion. The IRS instructions require year-end values, so a balance that remains in an IRA on December 31 can affect the calculation even if the conversion itself happened earlier.

Form 8606 errors often begin with treating an account as isolated. Another common mistake is omitting a nondeductible contribution or failing to carry basis information into the calculation. The form is the record of that basis and conversion; retain the relevant account and tax records and follow the instructions for the year involved.

Does the pro-rata rule include SEP and SIMPLE IRAs?

Yes. For Form 8606’s year-end balance calculation, the IRS instructions include traditional SEP and SIMPLE IRAs in traditional IRA value unless a specific instruction says otherwise.

That means a SEP or SIMPLE IRA balance can affect the taxable share even if the new nondeductible contribution sits in a separate traditional IRA. The IRS also says conversions from a traditional IRA, SEP IRA, or SIMPLE IRA to a Roth IRA are reported on Form 8606. A separate custodian or account label does not, by itself, remove an IRA from the calculation.

Before converting, people with pre-tax IRA assets commonly compare three paths: convert with the existing balance and account for the taxable portion; leave the balance in place and accept the pro-rata result; or ask whether an employer plan accepts eligible pre-tax IRA assets. The third path is often called a reverse rollover. The IRS says an IRA can be rolled into a qualified retirement plan such as a 401(k) if the plan permits that type of rollover. Eligibility and plan terms matter.

Schwab notes that moving eligible pre-tax assets into an accepting 401(k) can leave after-tax IRA basis available for conversion under the taxpayer’s actual circumstances. That move also places the assets under plan rules and may mean fewer investment choices than an IRA. Compare the tax calculation with the plan’s rollover terms before deciding how to handle the balance.