The backdoor Roth IRA calculator helps high-income earners understand the tax implications of converting a non-deductible IRA contribution to a Roth IRA. The pro-rata rule determines how much of your conversion is taxable — and this tool calculates it for you.
IRA Conversion Details
2026 IRA contribution limit is $7,000 ($8,000 if 50+)
Total non-deductible contributions (Form 8606)
Include all traditional, SEP, and SIMPLE IRA balances
How the Backdoor Roth IRA Works
The backdoor Roth IRA is a workaround for high earners who cannot contribute directly to a Roth IRA due to income limits ($161,000 for singles, $240,000 for married filing jointly in 2026).
The Two-Step Process
Step 1: Make a non-deductible contribution to a traditional IRA ($7,000 for 2026 or $8,000 if 50+). Step 2: Convert the traditional IRA to a Roth IRA. If done quickly and you have no other pre-tax IRA money, this conversion is largely tax-free — you already paid income tax on the contribution.
The Pro-Rata Rule Problem
If you have other traditional IRA accounts (like a rollover IRA from a former employer), the pro-rata rule says you can't selectively convert only the after-tax money. The IRS treats all your traditional IRA funds as one pool, and each dollar converted is partially taxable based on the ratio of pre-tax to total IRA funds.
When Backdoor Roth Is Cleanest
The backdoor Roth is cleanest when you have zero pre-tax IRA balance. If you have an old rollover IRA, consider whether your current 401k accepts incoming rollovers — rolling the pre-tax IRA into the 401k eliminates the pro-rata problem for Roth conversions.
Frequently Asked Questions
Is this backdoor Roth calculator free?
Yes, completely free with no signup required. All calculations run locally in your browser.
Is my data private?
Absolutely. All calculations happen in your browser. No data is sent to any server.
What is a backdoor Roth IRA?
A backdoor Roth IRA is a strategy for high-income earners who exceed the Roth IRA income limits. You make a non-deductible contribution to a traditional IRA and then convert it to a Roth IRA. The conversion is typically tax-free if done quickly and you have no other pre-tax IRA funds.
What is the pro-rata rule?
The pro-rata rule requires you to calculate the taxable portion of a Roth conversion based on the ratio of your pre-tax IRA money to your total IRA money. If you have $100,000 in a rollover IRA and convert $7,000, you can't just convert the non-deductible $7,000 tax-free — a proportional amount of each dollar is pre-tax.
How do I avoid the pro-rata rule?
The cleanest way is to have zero pre-tax IRA money when you do the conversion. You can roll your traditional IRA into a 401k (if your plan allows) to eliminate the pre-tax IRA balance, then convert only the non-deductible contribution.
What is IRA basis?
IRA basis is the total of all non-deductible contributions you've made to traditional IRAs. This is tracked on Form 8606 each year you make a non-deductible contribution. Your basis is not taxed when withdrawn — only the pre-tax portion is.