401(k) Calculators
401(k) to Roth IRA Conversion Calculator
The conversion itself never triggers a penalty — but how you pay the tax bill can quietly erase the entire benefit of converting in the first place.
Compare converting vs. staying traditional
Same growth assumption, evaluated over your real time horizon.
Convert to Roth
Grows tax-free, no tax at withdrawal
Stay traditional
Grows tax-deferred, taxed at withdrawal
Assumes the traditional account faces the same growth rate, and applies your entered future tax rate to the entire traditional balance at withdrawal. Doesn't model RMDs, IRMAA thresholds, or multi-year bracket-filling conversion strategies — a financial advisor can help model those refinements.
The rule most people get wrong: the conversion itself is never penalized
A common fear is that converting before age 59½ triggers the 10% early withdrawal penalty. It doesn't — moving money between retirement accounts via a proper conversion isn't a distribution at all, so no penalty applies to the conversion itself, regardless of your age. What can trigger a penalty is withdrawing the converted amount too soon afterward.
The 5-year rule for conversions (different from the contribution 5-year rule)
The single factor that determines whether conversion actually helps
How you pay the tax bill on conversion matters more than almost any other variable in the decision. Pay it from savings outside the retirement account, and the full converted amount keeps growing tax-free — that's where the real advantage comes from. Pay it by withholding from the converted amount itself, and you're not only paying the tax — you're also permanently shrinking the amount that gets to grow tax-free, which can erase the benefit of converting at all, or even make it a net loss compared to just staying traditional.
What actually makes a conversion worth it
- Your tax rate now is lower than you expect it to be later — the classic case for converting, common in a low-income year (early retirement before Social Security, a career gap, or a year with unusually low income).
- You can pay the tax from outside funds, not from the converted amount.
- You have a long time horizon for the converted funds to grow tax-free before you need them.
- You want to reduce future RMDs — Roth IRAs (and, since SECURE 2.0, Roth 401(k)/403(b) accounts too) have no required minimum distributions during the original owner's lifetime, while traditional accounts force withdrawals starting at age 73 (rising to 75 for those born in 1960 or later).
No income limits on conversions — unlike direct Roth contributions
Direct Roth IRA contributions phase out at higher incomes, but conversions have no income limit at all — you can convert any amount regardless of how much you earn, which is exactly why high earners use conversions (including the "backdoor Roth" technique) to get money into a Roth when they can't contribute directly.
Conversion tax mechanics, the 5-year rule for conversions specifically, and current RMD ages (73, rising to 75 for those born 1960+) verified against multiple independent 2026 tax and financial planning guides. This is a planning estimate — a financial advisor can model your specific bracket-filling strategy, RMD impact, and IRMAA considerations.
Frequently asked questions
Before you convert a 401(k) to a Roth IRA.
Does converting a 401(k) to a Roth IRA trigger the 10% early withdrawal penalty?
No — the conversion itself is never subject to the penalty, regardless of age. The penalty can apply later if you withdraw the converted amount within 5 years of that specific conversion and you're under 59½.
How is a Roth conversion taxed?
The full amount converted is added to your taxable income for the year and taxed at ordinary income rates — it's not capital gains tax, since the original 401(k) contributions were pre-tax.
Should I pay the conversion tax from the converted funds or from savings?
From outside savings, if at all possible. Paying from the converted amount itself reduces how much actually grows tax-free in the Roth, which can significantly reduce or even eliminate the benefit of converting.
Are there income limits on Roth conversions?
No — unlike direct Roth IRA contributions, which phase out at higher incomes, conversions have no income limit at all, which is why high earners commonly use them to get money into a Roth account.
Why do people convert to avoid future RMDs?
Traditional 401(k)s and IRAs require minimum distributions starting at age 73 (75 for those born 1960 or later), forcing taxable withdrawals whether you need the money or not. Roth IRAs have no RMDs during the original owner's lifetime.