Retirement
Roth Conversion Calculator
Converting means volunteering for a tax bill today so the balance grows tax-free forever. Whether that pays comes down to one comparison — your rate now against your rate when you would have withdrawn — plus whether you can pay the tax from outside the account.
Tested against worked examplesHow we verify
The conversion is ordinary income and can push you into the next bracket.
Converting comes out ahead by: $5,518
Converting comes out ahead by
$5,518
Measured at your horizon, after the tax each path eventually pays.
- Tax due this year
- $22,000
- Amount landing in the Roth
- $100,000
- Roth at your horizon
- $275,903
- Traditional after withdrawal tax
- $209,686
- What the tax money would have grown to
- $60,699
Entirely tax-free, and never subject to RMDs.
Counted against the conversion — that cash could have stayed invested.
Compare scenariosTry three values of one input
| Amount to convert | |||
|---|---|---|---|
| Converting comes out ahead by | $4,966 | $5,518+$552 | $6,070+$1,104 |
| Tax due this year | $19,800 | $22,000+$2,200 | $24,200+$4,400 |
| Amount landing in the Roth | $90,000 | $100,000+$10,000 | $110,000+$20,000 |
| Roth at your horizon | $248,313 | $275,903+$27,590 | $303,493+$55,181 |
| Traditional after withdrawal tax | $188,718 | $209,686+$20,969 | $230,655+$41,937 |
| What the tax money would have grown to | $54,629 | $60,699+$6,070 | $66,769+$12,140 |
Every other input stays at the value you set above — currently $100,000 for amount to convert. Differences are measured against the first column.
Saved scenariosSave this calculation
Saved in this browser only — no account, and nothing is sent to us. Clearing your browser data deletes them.
How this calculator works
The Roth path grows the amount that actually lands in the account at the given return, and is worth its full balance at the horizon. The traditional path grows the whole amount and is then reduced by your expected future rate. When outside cash pays the tax, that cash is credited to the traditional path as a side account growing at the same return, so the comparison isolates the account wrapper rather than rewarding one path with extra money.
A single flat rate stands in for a progressive bracket table on both sides, and state tax, IRMAA surcharges, the taxation of Social Security, and the five-year rules are not modelled. Large conversions frequently span brackets — a bracket-aware projection from a tax professional is the right tool before acting.
What this assumes
- Tax is paid at the marginal rate you enter, in the year of conversion, and ideally from outside the account.
- The pro-rata rule applies if you hold non-deductible basis across your IRAs.
- Each conversion starts its own five-year clock before the converted amount can be withdrawn penalty-free.
What changes this number
- Your rate this year versus later
- The whole decision. Converting in a low-income year — a career break, or the window between retiring and claiming Social Security — is where this pays.
- Paying the tax from outside
- Using the balance itself to pay shrinks the amount that goes on compounding tax-free, which is most of the benefit.
- Bracket capacity
- Converting just enough to fill a lower bracket, repeated over several years, beats one large conversion that spills into a higher one.
A worked example
Take the $100k at 22% now vs 24% later scenario. These figures are produced by the calculator above, not written alongside it, so they always match what the tool returns.
What you enter
- Amount to convert
- $100,000
- Your marginal rate today
- 22%
- Expected rate at withdrawal
- 24%
- Years until you withdraw
- 15 years
What it returns
- Converting comes out ahead by
- $5,518
- Tax due this year
- $22,000
- Amount landing in the Roth
- $100,000
- Roth at your horizon
- $275,903
- Traditional after withdrawal tax
- $209,686
Try an example
Frequently asked questions
When does a Roth conversion make sense?
When your rate today is lower than the rate you expect at withdrawal. That happens in a gap year between jobs, early retirement before Social Security and RMDs begin, or when you believe rates will rise. It also helps heirs, who inherit a Roth with no income tax on withdrawals.
Should I pay the conversion tax from the IRA?
Ideally not. Withholding from the conversion means less money makes it into the Roth, and before 59½ the withheld amount counts as an early distribution with a 10% penalty on top. Conversions are strongest when you have taxable savings to cover the bill.
What is the five-year rule?
Each conversion has its own five-year clock. Withdraw converted principal before that clock runs out and before 59½, and you owe a 10% penalty even though the tax was already paid. Earnings have a separate five-year rule tied to your first Roth contribution.
Can I undo a conversion?
No. Recharacterising a conversion was eliminated by the 2017 tax law. Once you convert, it is permanent — which is why people convert in slices across several years rather than all at once, and often wait until late in the year when income is known.
How does a conversion affect Medicare premiums?
Conversion income counts toward the IRMAA thresholds that set Medicare Part B and D premiums, on a two-year lag. A conversion at 63 can raise premiums at 65. It can also increase the taxable portion of Social Security. Both are real costs this calculator does not model.
Related calculators
Roth IRA Calculator
Project your Roth IRA's tax-free value at retirement and see how much of it is earnings you'll never pay tax on. Uses the 2026 limit of $7,500.
Traditional IRA Calculator
Project your traditional IRA at retirement, see this year's tax deduction, and estimate the tax you'll owe on withdrawals. Uses the 2026 limit of $7,500.
RMD Calculator
Calculate your required minimum distribution from a traditional IRA or 401(k) using the IRS Uniform Lifetime Table, with the tax due and a projection of future years.
Retirement Calculator
Project your retirement savings: what your balance could reach by retirement age and the monthly income it could sustainably provide.
Disclaimer: DayCents provides this calculator for educational purposes only. Results are estimates based on your inputs and the stated assumptions — they are not financial advice, a quote, or an offer of credit. Consult a qualified financial professional before making major money decisions.