Free roth ira conversion calculator
See whether converting a traditional IRA to a Roth pays off — the tax due now versus the tax saved later, updated live, as you type.
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Estimates only, based on a constant real return and steady saving. Not financial advice.
Results are estimates. Consult a professional.
What is a Roth IRA conversion?
A Roth IRA conversion moves money from a pre-tax retirement account — a traditional IRA, a SEP, a SIMPLE, or an old 401(k) — into a Roth IRA. You pay ordinary income tax on the converted amount in the year you convert, and in exchange the money grows tax-free and comes out tax-free in retirement. This Roth IRA conversion calculator shows the one trade that decides whether it pays off: the tax you owe now versus the tax you would owe later.
The defining feature of a conversion is that anyone can do one. There is no income limit on conversions — the cap that used to block high earners was removed in 2010. That is what separates a conversion from a direct Roth contribution (which phases out by income) and from the backdoor and mega-backdoor strategies that exist only to work around that income cap.
How a Roth conversion is calculated
A conversion is a bet on tax rates. Leaving the money in a traditional account, it grows untaxed and is taxed once at your future rate when you withdraw. Converting it, you pay tax at your current rate today, and it grows and withdraws tax-free. The calculator compares the two ending values side by side:
How to use the Roth conversion calculator
- Amount available. The pre-tax balance you intend to convert. You can convert any portion of an IRA — you do not have to do it all at once.
- Current tax rate. Your marginal rate this year, including the conversion. Because the conversion adds to your taxable income, estimate the rate the top of the conversion will actually land in.
- Withdrawal tax rate. The marginal rate you expect in retirement when you would otherwise have drawn the traditional money down.
- Annual return. The growth rate you assume for both accounts — it must be the same for both so the comparison is fair.
- Years until withdrawal. The longer the runway, the more tax-free compounding favours the Roth side.
A worked example: converting $100,000
Priya holds $100,000 in a traditional IRA. She is in the 22% bracket today but expects to be in the 32% bracket in retirement (a pension plus large RMDs). She assumes a 7% return over 20 years. To reproduce this on the calculator, set Amount = 100000, Current tax rate = 22, Withdrawal tax rate = 32, Annual return = 7, Years = 20.
Step 1 — The tax due now
Converting $100,000 adds $100,000 to this year's taxable income. At 22%, the tax due now is $100,000 × 22% = $22,000. The calculator funds this from the conversion, so $78,000 of after-tax money lands in the Roth.
Step 2 — Grow both sides for 20 years
Step 3 — Read the result
The pro-rata rule on conversions
If your traditional IRAs hold a mix of pre-tax and after-tax money, you cannot choose to convert only the after-tax dollars. The IRS pro-rata rule treats every dollar across all of your traditional, SEP, and SIMPLE IRAs as one pool, valued on December 31 of the conversion year. Your conversion is taxable in the same proportion that pre-tax money makes up that whole pool, and you report it on Form 8606.
| IRA holdings (Dec 31) | Pre-tax | After-tax basis | Taxable share of a $7,000 conversion |
|---|---|---|---|
| $0 pre-tax (clean) | $0 | $7,000 | 0% — fully tax-free |
| $43,000 rollover + $7,000 basis | $43,000 | $7,000 | 86% — $6,020 taxable |
| $93,000 rollover + $7,000 basis | $93,000 | $7,000 | 93% — $6,510 taxable |
Pro-rata makes a conversion taxable in proportion to pre-tax dollars in ALL your IRAs. This calculator applies one flat tax rate and does not model pro-rata — figure your taxable fraction on Form 8606.
IRS — Form 8606 (Nondeductible IRAs) is used to figure the taxable portion of a conversion when after-tax basis is present.2025 limits, the five-year clock, and RMDs
There is no dollar cap on how much you can convert in a year, but several rules shape the decision. Each conversion starts its own five-year clock: withdraw converted principal before five years have passed and before age 59½ and you can owe the 10% early-withdrawal penalty on it. Converting also permanently removes that money from future required minimum distributions, which begin at age 73 under SECURE 2.0.
| Rule (2025) | Figure | Notes |
|---|---|---|
| Conversion income limit | None | Anyone can convert any amount — removed in 2010. |
| Roth IRA direct-contribution phase-out (single) | $150,000–$165,000 MAGI | Why high earners convert instead of contributing. |
| Roth IRA direct-contribution phase-out (MFJ) | $236,000–$246,000 MAGI | Above the top, direct Roth contributions are barred. |
| Early-withdrawal penalty (under 59½) | 10% | Applies to converted principal within the 5-year window. |
| RMD start age (SECURE 2.0) | 73 | Rising to 75 in 2033; Roth IRAs have no lifetime RMDs. |
2025 figures published by the IRS. The direct-contribution phase-out is shown because it is the reason conversions and backdoor Roths exist.
IRS — 401(k) limit increases to $23,500 for 2025; Roth IRA phase-out ranges and IRA limits for 2025.IRS — Retirement plan and IRA required minimum distributions FAQs (RMD age 73 under SECURE 2.0).Who benefits most from a Roth conversion
- People in a temporary low-income year. A gap year, early retirement before Social Security and RMDs begin, or a low-earnings sabbatical creates a window to convert at a low marginal rate.
- Those expecting higher future rates. If pensions, Social Security, and RMDs will stack you into a higher bracket later — or if you believe rates will rise — paying tax now can win.
- Estate planners. Roth IRAs carry no lifetime RMDs, so they can grow untouched and pass to heirs, who then have ten years of tax-free growth before they must empty the account.
- Savers managing IRMAA and RMDs. Converting in your 60s shrinks the traditional balance that drives RMDs and Medicare premium surcharges later.
The reverse is also true: if you expect a lower tax rate in retirement, or you would have to pay the conversion tax from the IRA itself at a high rate, leaving the money pre-tax is often the stronger move. Compare the two head-on with the Roth IRA vs traditional IRA calculator.
Conversion gotchas and common mistakes
- Paying the tax from the IRA. The strongest conversions pay the tax with outside cash so the full balance lands in the Roth. Using the IRA to cover the tax shrinks the Roth and, if you are under 59½, the withheld amount can itself be a penalised early withdrawal. This calculator simplifies by funding the tax from the conversion.
- Converting too much in one year. A large conversion can push you into a higher bracket, raise Medicare IRMAA surcharges two years later, and tax more of your Social Security. Many people convert in measured slices to "fill up" a bracket.
- Forgetting the pro-rata rule. Assuming an after-tax contribution converts tax-free when you hold other pre-tax IRA money — the most expensive surprise.
- Recharacterizing a conversion. You no longer can. Since 2018, a Roth conversion is irreversible — once done, it cannot be undone.
- Ignoring the five-year clock. Each conversion has its own clock for penalty-free access to the converted principal.
Accuracy, assumptions, and sources
This Roth IRA conversion calculator compares a single converted amount under two tax timings using a fixed return and the rates you enter. It applies one flat marginal rate to the conversion and funds the tax from the converted balance; it does not model bracket-by-bracket stacking, state tax, the pro-rata rule, IRMAA, or the five-year clock. Treat the result as a planning estimate, not tax advice. Tax law is specific to your situation — confirm any conversion with a CPA or tax professional and verify current figures on IRS.gov.
IRS — Roth IRAs (conversion rules and taxation).IRS — Rollovers of retirement plan and IRA distributions.Frequently asked questions about the free roth ira conversion calculator
About this Roth IRA conversion calculator
This calculator compares keeping money in a traditional IRA against converting it to a Roth, weighing the income tax you pay now at your current rate against the tax you would owe later at your expected retirement rate. It is built for the one decision a conversion turns on: whether your future tax rate will be higher than today's.
It sits alongside our other retirement calculators, and you can browse every tool on the site from the full calculator directory. Figures are 2025 IRS limits; results are planning estimates, not tax advice.