Roth Conversion Calculator
Should you convert traditional 401(k) or IRA money to Roth — and how much each year? This free planner runs your plan year by year with federal and state taxes, bracket fill-up, RMDs, and Social Security taxation, then shows whether converting leaves you with more after-tax wealth.
Open the free Roth Conversion Planner →Free, no account, no email — your numbers stay in your browser.
What a Roth conversion does
A Roth conversion moves money from a pretax account (traditional 401(k) or IRA) into a Roth, where it grows tax-free and is never subject to required minimum distributions. You pay ordinary income tax on the amount converted now — the whole strategy is about paying that tax at a lower rate today than you'd pay on withdrawals later.
- Fill your low brackets. The best conversions happen in "gap years" — after you retire but before Social Security and RMDs push your income up — when there's room at the top of the 12% or 22% bracket.
- Shrink future RMDs. Every dollar converted is a dollar that won't be forced out (and taxed) at 73 or 75, when a large pretax balance can spike you into a higher bracket for life.
- Protect the survivor. For couples, converting reduces the tax hit when one spouse dies and the survivor files as single.
Watch the Social Security "tax torpedo"
Converting while you're already collecting Social Security can pull more of your benefit into taxable income — up to 85% of it — pushing your effective rate above your bracket. The planner flags this and compares converting in your gap years versus later, so you can see when to convert and when to wait.
Frequently asked questions
Is a Roth conversion worth it?
It's worth it when you can pay tax on the conversion at a lower rate today than you'd pay on withdrawals later — often true in the gap years between retiring and starting Social Security and RMDs. The calculator compares converting versus doing nothing across your whole plan.
How much should I convert to Roth each year?
A common strategy is to 'fill the bracket' — convert just enough to reach the top of your current tax bracket (say 12% or 22%) without spilling into the next one. The planner sizes conversions to a bracket you choose and shows the tax each year.
Do Roth conversions affect my Social Security taxes?
Yes. A conversion adds to your provisional income, which can make more of your Social Security benefit taxable — up to 85%. Converting before you claim Social Security usually avoids this 'tax torpedo.' The tool models it explicitly.
Does the calculator include state taxes?
Yes — pick your state and it applies an approximate state income-tax rate to conversions and other ordinary income, on top of federal tax.
Is this Roth conversion calculator free?
Yes — completely free and private, with no account and no email. Your numbers stay in your browser.