How do I avoid the pro-rata tax on a backdoor Roth?

Roll existing pre-tax IRA money into your employer 401(k) before December 31 of the conversion year. With a $0 pre-tax IRA balance, the backdoor conversion is essentially tax-free.

Backdoor Roth IRA Calculator — Conversion Tax & Pro-Rata Rule

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Backdoor Roth

Conversion tax • Pro-rata • Growth

Nondeductible contribution

Existing pre-tax IRA balance ⓘ

Your marginal tax rate

Years until retirement

yrs

Expected annual return

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Enter your contribution to see the conversion

How the Backdoor Roth Calculator Works

Enter your nondeductible contribution to a traditional IRA (2026 limit is $7,000, or $8,000 if 50+).
Add any existing pre-tax IRA balance — this triggers the pro-rata rule.
See the taxable amount, tax owed, and tax-free growth over time.

What Is a Backdoor Roth IRA?

A backdoor Roth lets high earners — who are above the Roth IRA income limits — still get money into a Roth. You make a nondeductible contribution to a traditional IRA, then convert it to a Roth. If you have no other pre-tax IRA money, the conversion is essentially tax-free, and all future growth comes out tax-free in retirement.

The catch is the IRS pro-rata rule: it treats all your traditional, SEP and SIMPLE IRAs as one pot. If part of that pot is pre-tax, a proportional share of your conversion is taxable. Example: convert $7,000 with $63,000 of pre-tax IRA money and 90% of the conversion is taxable. This calculator shows that split. The 2026 IRA contribution limit is $7,000 ($8,000 if age 50+). Estimate only — not tax advice.

Backdoor Roth FAQ

Is a backdoor Roth legal? ▾

Yes. It's a recognized, IRS-acknowledged strategy: a nondeductible traditional IRA contribution followed by a Roth conversion. There's no income limit on conversions.

What is the pro-rata rule? ▾

The IRS treats all your traditional, SEP and SIMPLE IRAs as one account. The taxable share of a conversion equals your pre-tax balance divided by your total IRA balance — so pre-tax money makes part of the conversion taxable.

How do I avoid the pro-rata tax? ▾

Roll existing pre-tax IRA money into your employer 401(k) before December 31 of the conversion year. With $0 pre-tax IRA balance, the backdoor conversion is essentially tax-free.

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