Key Takeaways
- A Roth conversion is a taxable event: the converted amount is added to your ordinary income and taxed at your marginal rate in the conversion year.
- The ideal time to convert is when your current tax rate is lower than your expected retirement tax rate — typically in low-income years, early retirement, or before RMDs begin at age 73.
- Always pay conversion taxes from non-IRA funds. Paying from the IRA reduces the converted amount and triggers a 10% early withdrawal penalty if you are under 59½.
- The backdoor Roth is for high earners above the direct contribution income limits ($165K single / $246K MFJ in 2025). The pro-rata rule applies if you have other pre-tax IRA funds.
- A Roth conversion ladder spreads conversions across multiple low-income years to minimize the total tax paid — especially effective in the gap between early retirement and age 73 (when RMDs start).
Table of Contents
- What is a Roth IRA Conversion?
- Roth Conversion Tax Calculator — How It Works
- Should I Convert to a Roth IRA?
- Roth IRA Conversion Calculator by State
- Backdoor Roth IRA Calculator
- Roth Conversion Ladder Calculator
- 2025 Federal Tax Brackets for Roth Conversions
- Tips & Common Mistakes
- Frequently Asked Questions
- Related Calculators
What is a Roth IRA Conversion?
A Roth IRA conversion is the process of moving funds from a pre-tax retirement account — a Traditional IRA, 401(k), 403(b), or SEP IRA — into a Roth IRA. The key distinction: Traditional IRA withdrawals are taxed as ordinary income in retirement, while Roth IRA withdrawals are completely tax-free. The conversion is the mechanism that moves money from the taxed-later bucket to the never-taxed bucket.
The trade-off is immediate: in the year you convert, the full converted amount is treated as ordinary income and taxed at your marginal rate. You pay taxes now so you never pay them on that money — or its growth — again. Whether that trade is worth making depends on your current tax rate, your expected retirement tax rate, how many years the money has to grow, and whether you can pay the conversion taxes from outside funds.
According to IRS Publication 590-A, there are no income limits on Roth conversions — anyone can convert regardless of income. This is different from direct Roth IRA contributions, which phase out above certain income thresholds.
Roth Conversion Tax Calculator — How It Works
Our Roth conversion tax calculator uses 2025 federal tax brackets to estimate exactly how much tax you will owe on a conversion, then projects the long-term value of the converted funds against the same amount staying in a Traditional IRA.
The Tax Calculation
The calculator adds your conversion amount to your existing income, then computes the federal tax using the actual 2025 marginal rate structure. The tax on the conversion is the difference between the tax on your income without the conversion and the tax on your income with it — this “stacking” effect means conversions can push you into a higher bracket on the last dollars converted.
Federal Tax on Conversion = Tax(Income + Conversion) − Tax(Income)
Total Tax = Federal Tax on Conversion + (Conversion × State Rate)
The Growth Projection
The calculator then projects both the Roth balance and the equivalent Traditional IRA balance at your specified retirement age, applying your expected annual return. At retirement, the Roth is shown at full value (tax-free), while the Traditional IRA is shown after applying your expected retirement tax rate — showing you the net after-tax advantage of the Roth over the holding period.
Should I Convert to a Roth IRA?
The answer to “should I convert to a Roth IRA?” depends on five key factors. Our calculator quantifies the first three; the remaining two require judgment.
1. Current vs. Retirement Tax Rate
This is the core of the decision. If you are in the 22% bracket now and expect to be in the 32% bracket in retirement (due to Social Security, RMDs, and investment income), converting now at 22% saves you 10 percentage points on every dollar converted. If you expect to be in a lower bracket in retirement, keeping the money in a Traditional IRA may be better.
2. Years Until Retirement
The longer the money has to grow tax-free, the more valuable the conversion. A $50,000 conversion at age 40 has 25+ years of compound growth before it is needed. The same conversion at 62 has far less time to recover the upfront tax cost.
3. Can You Pay the Tax from Non-IRA Funds?
This is critical. If you can pay the conversion tax from a taxable savings account, the entire converted amount stays in the Roth and grows tax-free. If you pay the tax from the IRA itself, you are effectively reducing the converted amount AND potentially triggering a 10% early withdrawal penalty if under 59½. Fidelity’s conversion guide consistently recommends paying conversion taxes from taxable accounts as the single most impactful optimization.
4. Impact on Current-Year Tax Situation
A large conversion can push you into a higher bracket, trigger the Net Investment Income Tax (NIIT) at 3.8%), phase out deductions, or increase Medicare Part B/D premiums (IRMAA surcharges). Consider the full impact on your tax return, not just the conversion tax in isolation.
5. RMD Planning
Roth IRAs are not subject to Required Minimum Distributions during the owner’s lifetime. Converting before age 73 (when RMDs begin for Traditional IRAs) can reduce or eliminate mandatory withdrawals that would otherwise be taxed as ordinary income — a major benefit for those who do not need the funds for living expenses.
Roth IRA Conversion Calculator by State
Nine states have no state income tax: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. In these states, the total tax cost of a Roth conversion equals only the federal portion — making conversions significantly more attractive.
In high-tax states, the state tax adds a meaningful cost. A $100,000 conversion in California at the top state rate (13.3%) could add over $13,000 in state tax on top of federal liability. Our Roth IRA conversion calculator by state lets you select your state to include the applicable state rate automatically.
| State Tax Impact | States | Effect on Conversion Cost |
|---|---|---|
| No state tax | AK, FL, NV, NH, SD, TN, TX, WA, WY | Most favorable — federal tax only |
| Low state tax (under 4%) | AZ (2.5%), CO (4.4%), IN (3.05%), PA (3.07%), ND (2.5%) | Modest additional cost |
| Medium state tax (4–7%) | GA, IL, MA, MI, UT, VA, WV, most others | Adds 4–7% to conversion cost |
| High state tax (7%+) | CA (up to 13.3%), NY (up to 10.9%), NJ (up to 10.75%), MN (up to 9.85%), OR (up to 9.9%) | Significantly increases conversion cost — consider timing or relocation before converting |
Backdoor Roth IRA Calculator
The backdoor Roth IRA is a two-step strategy that allows high earners to contribute to a Roth IRA despite exceeding the income limits for direct contributions. In 2025, direct Roth IRA contributions phase out at $150,000–$165,000 for single filers and $236,000–$246,000 for married filing jointly.
How the Backdoor Roth Works
- Make a non-deductible contribution to a Traditional IRA (up to $7,000 in 2025, $8,000 if age 50+)
- Convert the Traditional IRA to Roth shortly after the contribution
If you have no other pre-tax IRA funds, the conversion is essentially tax-free (you contributed after-tax dollars, so converting them creates no additional tax). However, the pro-rata rule creates a complication if you have other pre-tax IRA money.
The Pro-Rata Rule
The IRS treats all your Traditional, SEP, and SIMPLE IRA funds as one pool when calculating how much of a conversion is taxable. If you have $100,000 in pre-tax IRA funds and convert $7,000 in after-tax funds, you cannot isolate the after-tax contribution — the taxable percentage is determined by the ratio of pre-tax to total IRA funds.
Taxable % = Pre-Tax IRA Balance ÷ Total IRA Balance
Tax-Free % = After-Tax (Non-Deductible) ÷ Total IRA Balance
Example: You have $93,000 in a rollover IRA (pre-tax) and contribute $7,000 non-deductibly. Total IRA = $100,000. Pre-tax ratio = 93%. If you convert $7,000, 93% of the conversion ($6,510) is taxable. Use our backdoor Roth calculator above to calculate your exact taxable portion. According to Vanguard’s backdoor Roth guide, the solution to this problem is to roll your pre-tax IRA funds into a workplace 401(k) before executing the backdoor Roth, eliminating the pro-rata issue entirely.
Roth Conversion Ladder Calculator
A Roth conversion ladder is a strategy of converting a fixed amount from a Traditional IRA to a Roth IRA each year, deliberately sized to stay within a target tax bracket. Rather than converting a large sum all at once (which could spike you into the 32% or 35% bracket), you convert just enough each year to fill up a lower bracket.
The ladder is most powerful during the years between retirement and age 73, when you may have lower income than during your working years but before Social Security, RMDs, and other income sources create bracket compression. This window — sometimes called the “Roth conversion sweet spot” — is when conversions are cheapest.
How the Ladder Works
Step 1: Calculate your income from all sources except IRA withdrawals (Social Security, pension, part-time work). Step 2: Find how much headroom you have before reaching the top of your target bracket. Step 3: Convert exactly that amount each year. Step 4: Repeat until the Traditional IRA is fully converted or until other income sources reduce the available headroom.
Note that Roth conversions have a 5-year holding period before the converted funds can be withdrawn penalty-free if you are under 59½. The conversion ladder accounts for this — plan conversions at least 5 years before you need to access those specific funds. This is detailed in IRS Publication 590-B.
2025 Federal Tax Brackets for Roth Conversions
The tables below show the 2025 federal income tax brackets for the two most common filing statuses. Your Roth conversion is added on top of your existing income and taxed starting where your ordinary income leaves off.
| Rate | Single Filer (2025) | Married Filing Jointly (2025) |
|---|---|---|
| 10% | $0 – $11,925 | $0 – $23,850 |
| 12% | $11,926 – $48,475 | $23,851 – $96,950 |
| 22% | $48,476 – $103,350 | $96,951 – $206,700 |
| 24% | $103,351 – $197,300 | $206,701 – $394,600 |
| 32% | $197,301 – $250,525 | $394,601 – $501,050 |
| 35% | $250,526 – $626,350 | $501,051 – $751,600 |
| 37% | Over $626,350 | Over $751,600 |
Source: IRS Revenue Procedure 2024-40. Standard deduction for 2025: $15,000 (single), $30,000 (MFJ). These figures are not pre-applied in our calculator — enter your AGI after your standard deduction for the most accurate result.
Tips & Common Roth Conversion Mistakes
| Common Mistake | What to Do Instead |
|---|---|
| Paying conversion tax from the IRA itself | Always pay conversion taxes from a taxable savings or brokerage account. Paying from the IRA reduces the amount that grows tax-free and can trigger a 10% early withdrawal penalty if under 59½. |
| Converting too much and spiking into a higher bracket | Calculate exactly how much headroom you have in your current bracket before converting. Our calculator shows the marginal rate and effective rate so you can right-size the conversion. |
| Ignoring the pro-rata rule for backdoor Roth | If you have pre-tax IRA funds, the pro-rata rule will make most of your backdoor conversion taxable. Roll pre-tax funds into your 401(k) first, then execute the backdoor. |
| Not considering IRMAA Medicare surcharges | Large conversions can push your MAGI above Medicare IRMAA thresholds ($106,000 single / $212,000 MFJ in 2025), adding $500–$4,000+ per year in Medicare Part B/D premiums with a two-year lookback. |
| Converting in a high-income year instead of waiting for a low-income year | The best years to convert are low-income years: early retirement before Social Security, sabbatical, career change, or years with large itemized deductions. Converting in a 32% year when a 22% year is coming wastes 10 points. |
| Forgetting the 5-year rule for conversions under age 59½ | Each Roth conversion has its own 5-year clock. Converted funds cannot be withdrawn penalty-free until 5 years after the conversion, even if you have an older Roth account. Plan conversions at least 5 years before you need access. |
Frequently Asked Questions
How much tax will I pay on a Roth conversion?
The tax on a Roth conversion equals the conversion amount multiplied by your marginal federal income tax rate, plus any applicable state income tax. The converted amount is added to your ordinary income for the year, so it is taxed at the top of your tax bracket (stacking on top of your existing income). Use our Roth conversion tax calculator above — enter your income, filing status, state, and conversion amount to get the exact federal + state tax estimate in seconds.
Should I convert to a Roth IRA?
Convert if: your current tax rate is lower than your expected retirement tax rate; you can pay the conversion tax from outside the IRA; you have many years for the Roth to grow; you want to reduce future RMDs; or you are in a temporarily low-income year. Delay or avoid conversion if: your current rate is higher than your expected retirement rate; you cannot pay the tax from outside the IRA; you are close to retirement with limited growth time; or the conversion would trigger IRMAA Medicare surcharges. The “should I convert to Roth IRA calculator” tab above runs all of these numbers for your specific situation.
What is the pro-rata rule for backdoor Roth?
The pro-rata rule requires you to calculate your taxable conversion percentage based on the ratio of pre-tax IRA funds to total IRA funds across all your Traditional, SEP, and SIMPLE IRAs. If you have $93,000 in pre-tax IRAs and add $7,000 in non-deductible contributions, 93% of any conversion is taxable. To avoid the pro-rata rule: roll all pre-tax IRA funds into your employer’s 401(k) before making the non-deductible contribution. Our backdoor Roth calculator above calculates your exact taxable portion.
What is the Roth conversion income limit in 2025?
There is no income limit for Roth conversions. Any amount can be converted from a Traditional IRA to a Roth IRA regardless of your income. The income limits ($150,000–$165,000 for single, $236,000–$246,000 for MFJ in 2025) apply only to direct Roth IRA contributions, not to conversions. This is why the backdoor Roth strategy works — high earners cannot contribute directly to a Roth, but they can convert via the backdoor.
Is it better to do a Roth conversion in a low-income year?
Yes — the lower your income in the conversion year, the lower the marginal rate applied to the converted amount, and the less tax you pay. The ideal conversion years are: early retirement before collecting Social Security; a gap year or career transition with lower-than-normal income; years with large itemized deductions (medical, charitable) that reduce taxable income; the years between early retirement and age 73 (when RMDs begin). Our Roth conversion ladder calculator above helps you plan which years and amounts to convert to minimize total lifetime tax.
Can I convert a 401(k) to a Roth IRA?
Yes. You can roll a 401(k), 403(b), or 457(b) directly to a Roth IRA in a taxable conversion. The conversion is treated the same way — the full pre-tax amount rolled is added to your income and taxed in the conversion year. You can also roll it first to a Traditional IRA and then convert to Roth, giving you more control over the timing and amount. Fidelity’s 401(k) rollover guide covers the mechanics in detail.
What is the 5-year rule for Roth conversions?
Each Roth conversion has its own 5-year holding period. The principal amount of a conversion cannot be withdrawn penalty-free until 5 years after the conversion year, unless you are over 59½. This is different from the 5-year rule for Roth IRA contributions (which starts when your first Roth account was opened). If you are under 59½ and plan to access converted funds, plan conversions at least 5 years before you need them. After age 59½ and with an account open for at least 5 years, all Roth withdrawals are completely tax and penalty-free. See IRS Publication 590-B for the full rules.
Related Calculators
If this Roth IRA conversion calculator helped you plan your retirement tax strategy, these tools complete the financial picture:
- Business Valuation Calculator — if your retirement strategy includes selling a business, estimate its value before planning your IRA conversion strategy.
- Break-Even Calculator — understand the break-even point of your conversion: how many years until Roth tax-free growth exceeds the upfront tax cost.
- Sales Tax Calculator — calculate exact sales tax for any purchase in retirement planning decisions.
- Age Calculator — calculate exactly how many years until retirement or until RMDs begin at age 73.