How to use this calculator
- Choose the tax year the contribution is for, your filing status, and your age on December 31 of that year.
- Enter your modified AGI (your AGI before any IRA deduction, for both of you on a joint return) and your taxable compensation (pay for work). The two are separate because the income limit reads one and the contribution limit the other.
- Say whether you have a retirement plan at work, from box 13 of your W-2, and, if you are married, whether your spouse does. Coverage only changes how much of a traditional IRA contribution you can deduct.
- If the answer shows a backdoor Roth, enter the value of all your traditional IRAs on December 31. That balance decides how much of the conversion is taxed.
- Under More options, enter a set amount instead of the most you can, any Roth conversion income already in your AGI, your spouse's pay for a spousal IRA, after-tax basis from last year's Form 8606, and the tax rates the comparison uses.
The answer gives the most you can put in a Roth IRA and, when your income limits it, what the backdoor adds in tax this year. The ranked list shows what this year's money leaves you after tax at retirement in a Roth IRA and in a traditional IRA, and the line under it gives the tax rate in retirement at which they trade places. "Show the numbers" has every limit and, with a backdoor, each Form 8606 line.
How it's calculated
1. The most you can put in all your IRAs
The limit is $7,500 for 2026, plus a $1,100 catch-up contribution if you are 50 or older by December 31, or your taxable compensation if that is less. Roth and traditional contributions share it. On a joint return, if you earn less than your spouse, your spouse's compensation less their own IRA contributions is added to yours.
2. The Roth limit by income
Below your filing status's income phase-out range you can put the whole limit in a Roth IRA; at its top or above, nothing. Inside it, the limit is L × (top − MAGI) ÷ width, rounded up to the next $10 and kept at $200 or more (or your compensation, if less) until it reaches zero, where L is the limit from step 1 and the width is the range's ($15,000 single or head of household, $10,000 joint or married filing separately). For the Roth limit only, Roth conversion income is taken out of your modified AGI. Single at $160,000 in 2026: $7,500 × ($168,000 − $160,000) ÷ $15,000 = $4,000.
3. The traditional IRA deduction
If neither you nor your spouse has a retirement plan at work, a traditional contribution is deductible at any income. Otherwise the deduction phases out over a range that depends on who is covered: for 2026, $81,000 to $91,000 for a covered single filer or head of household, $129,000 to $149,000 for a covered spouse filing jointly, $242,000 to $252,000 for a spouse who is not covered but whose spouse is, and $0 to $10,000 filing separately. The reduction is the dollar limit × (MAGI − bottom) ÷ width, rounded down to $10, and the deduction stays at least $200 (or your compensation, if less) until it reaches zero. Covered and single at $86,000, the most you can deduct is $3,750; the rest of a $7,500 contribution would be a nondeductible contribution.
4. The backdoor and Form 8606
When your income limits a direct Roth contribution, the rest of the amount goes in as a traditional IRA contribution and is then converted to a Roth IRA, both during the year. The pro-rata rule taxes the conversion in proportion to the pretax money in all your traditional IRAs. On Form 8606, line 10 is your after-tax basis (line 5) divided by your traditional IRAs' value on December 31 plus the amount converted (line 9), rounded to three places and at most 1.000; the conversion times that share is tax-free, and the rest is taxable. Single at $200,000, covered at work, with $50,000 in a rollover IRA: a $7,500 backdoor has a share of $7,500 ÷ $57,500 = 0.130, so $975 is tax-free and $6,525 taxable, adding $1,566 of federal tax. With no traditional IRA money on December 31, it would add none.
With no retirement plan at work for you or your spouse, the traditional contribution is deductible, so the backdoor is figured both ways and the cheaper one is used: deducting it and converting it means the deduction and the conversion's tax offset. In the example above without a plan at work, treating it as nondeductible would add $1,566 and deducting it adds $0.
5. Tax now
Each tax figure is the difference between two whole federal returns for the year, figured on the rate schedule with the standard deduction, qualified dividends and long-term gains at their own rates, and at 65 or older the extra standard deduction and the senior deduction. A deduction lowers the return's income; a conversion's taxable part raises it. A state rate, if you enter one, is applied to the deduction and the conversion's taxable part as your state allows. On the example filled in, deducting $7,500 saves $1,650 of federal tax.
6. Roth or traditional, at the same cost now
Both routes are compared for this year's money only, at the same cost to you now: whichever route costs less this year puts the difference in a taxable account, whose gain is taxed once, at retirement, at your rate on investment gains. The traditional IRA's withdrawals are taxed at your tax rate in retirement, apart from any nondeductible part; a Roth IRA's qualified distributions are tax-free. On the example, $7,500 grows at 7% for 30 years. In a Roth IRA it is $57,092 at 65. In a traditional IRA it is $50,241 after a 12.0% tax, and the $1,650 the deduction saved grows to $12,560 in a taxable account, $10,924 after tax at 15.0% on the gain: $61,165 in all. The routes come out even at a 19.1% tax rate in retirement: traditional leaves more below it, and Roth above it.
7. Growth
The same amount goes in at the start of each year, from your age now until the year before you retire, and grows at a steady return through each year. Each year's balance is figured exactly and rounded once. Putting in $7,500 at the start of each year until 65 would grow to $758,048 at a steady 7% a year.
Assumptions and limits
- Federal only. A flat state rate is optional, applied to your top dollars; it leaves out graduated state brackets and local income taxes. Two questions cover a state that does not allow the IRA deduction or does not tax conversions.
- The modified AGI and compensation are what you enter; they are not built from a return. The tax figures use your modified AGI as the return's income, which overstates AGI slightly if you have any of the add-backs. Refiguring for Social Security benefits (Publication 590-A, Appendix B) is not modeled.
- Tax now is figured on two whole federal returns with the standard deduction, the rate schedule, qualified dividends and long-term gains at their own rates, and, at 65 or older, the extra standard deduction and the 2025 to 2028 senior deduction; your spouse is taken to be your age. Credits, itemized deductions and the net investment income tax are left out.
- One person at a time. A couple runs it once for each spouse; the spousal IRA rule takes the other spouse's pay and IRA contributions as you enter them.
- The backdoor contribution and its conversion both happen during the year, the money earns nothing before it is converted, and no other IRA money comes out in the year.
- Growth assumes the same contribution every year at a steady return, with contributions at the start of each year. Future increases in the IRA limit, raises and changes in income are not projected.
- The Roth or traditional comparison is for this year's money only, at the same cost to you now, with the difference invested in a taxable account whose gain is taxed once at retirement.
- Traditional withdrawals are taxed at one rate in retirement, and Roth withdrawals are qualified. Required minimum distributions, early withdrawals and the 10% additional tax are not modeled.
- Employer contributions to SEP and SIMPLE IRAs, 529-to-Roth rollovers, repayments of reservist and disaster distributions, difficulty-of-care payments and the saver's credit are left out.
What this does not do
- Employer SEP and SIMPLE contributions, 529-to-Roth rollovers, or reservist and disaster repayments.
- The saver's credit or the net investment income tax, beyond a notice.
- Recharacterization of a contribution.
- Refiguring AGI for Social Security benefits.
- State rules beyond one flat rate and its two questions.
- Required minimum distributions, or inherited IRAs.
- The five-year rules for Roth withdrawals, beyond a notice.
- A backdoor contribution made after December 31 for the year before.
- Deducting part of a backdoor contribution where your deduction's own phase-out overlaps the Roth range: married filing jointly with only your spouse covered, or married filing separately.
- Minors and other dependents: a dependent's standard deduction is not modeled.
- The tax on a Roth conversion of money you already hold in traditional IRAs, beyond this year's backdoor.
Input field details
What to enter in each box, where to find the number, and how this calculator treats it. When two calculators give different answers from the same numbers, it's usually because they handle one of these differently.
Filing status
The status you file your federal return under for the year.
Where to find itThe filing status boxes at the top of Form 1040.
How this tool treats itIt sets which income range limits your Roth contribution and your deduction. For 2026 the Roth range is $153,000 to $168,000 for single and head of household and $242,000 to $252,000 for married filing jointly. A qualifying surviving spouse uses the joint ranges, as the IRS’s notices and worksheets show them. Married filing separately uses $0 to $10,000, unless you and your spouse lived apart all year: then the single ranges apply.
Your age at the end of the year
Your age on December 31 of the tax year.
How this tool treats itAt 50 or older you can add a catch-up contribution: $1,100 on top of the $7,500 limit for 2026. At 65 or older your standard deduction is larger and the senior deduction applies to the tax figures. If your birthday is January 1, the IRS treats you as a year older for the extra standard deduction at 65, which this age does not capture. There is no upper age limit for contributing.
Allowed range18 to 100
Not includedMinors and other dependents: a dependent’s standard deduction is not modeled.
Your modified AGI
Your adjusted gross income before any IRA deduction. For a joint return, the figure for both of you.
Where to find itForm 1040’s AGI line, plus any traditional IRA deduction and student loan interest deduction you took. Also add back any foreign earned income or housing exclusion, excluded savings bond interest or excluded adoption benefits. Leave out the backdoor conversion figured here. A negative AGI counts as 0.
How this tool treats itThe same figure sets your deduction and your Roth limit, except that Roth conversion income you enter under More options is taken out for the Roth limit. The tax figures also use it as your income, which overstates your income slightly if you have any of the add-backs.
Allowed range$0 to $10,000,000
Not includedRefiguring for Social Security benefits (Publication 590-A, Appendix B).
Your taxable compensation
Your pay for work for the year, not investment income.
Where to find itWages, salary, tips, commissions and bonuses, plus net self-employment earnings after the deductible part of self-employment tax and your own retirement plan contributions. Nontaxable combat pay counts, and so do taxable alimony under a divorce before 2019 and taxable fellowship or stipend payments for graduate study. Pensions, Social Security, interest and dividends do not.
How this tool treats itYou can contribute the IRA limit or your compensation, whichever is less. On a joint return, if you earn less than your spouse, your spouse’s compensation (less their own IRA contributions) counts toward your limit too.
Allowed range$0 to $10,000,000
I’m covered by a retirement plan at work
Leave it ticked if you were covered by a retirement plan at work for any part of the plan year.
Where to find itThe “Retirement plan” box in box 13 of your W-2.
How this tool treats itCovered means you could have contributed to, or your employer contributed to, a 401(k), 403(b), 457 plan of a government employer, pension, SEP or SIMPLE IRA for the plan year. It limits only how much of a traditional IRA contribution you can deduct: for 2026, the deduction phases out at $81,000 to $91,000 single or head of household, and $129,000 to $149,000 married filing jointly. It does not limit a Roth contribution.
My spouse is covered by a retirement plan at work
Tick it if your spouse was covered by a retirement plan at work, when you are married and file jointly, or file separately and lived together at any time in the year.
Where to find itBox 13 of your spouse’s W-2.
How this tool treats itIf you are not covered but your spouse is, your deduction phases out at $242,000 to $252,000 on a joint return for 2026, and $0 to $10,000 filing separately.
Value of all your traditional IRAs on December 31
The total value on December 31 of every traditional, rollover, and traditional SEP and SIMPLE IRA you own, after the backdoor’s conversion and not counting its money.
Where to find itYour December statements. Include any after-tax money in those IRAs and any rollover not finished by then. Leave out Roth IRAs, inherited IRAs, your spouse’s IRAs and workplace plans such as a 401(k). This is Form 8606, line 6.
How this tool treats itA backdoor Roth is a nondeductible contribution to a traditional IRA, converted to a Roth IRA. Under the pro-rata rule, all your traditional IRAs count as one, so the conversion is taxable in the same proportion as the pretax money in them on December 31: Form 8606 line 10, rounded to three places.
Allowed range$0 to $50,000,000
Retire at
The age you expect to stop contributing and start drawing on your IRAs.
How this tool treats itThe growth figures and the Roth or traditional comparison run to this age. At or below your age, growth is left out.
Allowed range19 to 100
Yearly return
The yearly return you expect on your IRA investments, after fund fees.
How this tool treats itThe same amount goes in at the start of each year and grows at this rate, compounded once a year. Returns are an assumption, not a forecast.
Allowed range0% to 20%
Put in the most I can
Leave it on to use the most the year allows you across all your IRAs; turn it off to enter your own amount.
How this tool treats itThe most is the IRA limit, plus the catch-up at 50 or older, or your taxable compensation if less. It is shared by all your traditional and Roth IRAs.
Amount to put in for the year
What you plan to contribute for the year, across all your IRAs.
How this tool treats itAbove the most you can put in, it is reduced to that amount. A contribution above the limit is an excess contribution, taxed 6% for each year it stays in the account at year end, unless you take it out, with what it earned, by your filing deadline including extensions.
Allowed range$0 to $100,000
Roth conversion income in your AGI
The taxable part of any traditional IRA you converted to a Roth this year, and of any workplace plan money rolled into a Roth IRA, if it is already in the AGI you entered.
Where to find itForm 8606, line 18, and the taxable amount on Form 1099-R for a rollover to a Roth IRA.
How this tool treats itIt counts for every other tax rule, but not for the Roth income limit, so it is taken out of your modified AGI for that limit only. It cannot be more than your AGI. Not the backdoor conversion figured here.
Allowed range$0 to $10,000,000
Qualified dividends and long-term gains in that AGI
The qualified dividends and net long-term capital gains already included in the AGI you entered.
Where to find itForm 1040’s qualified dividends line and Schedule D.
How this tool treats itTaxed at their own rates in the tax figures, so a deduction or a conversion can move the tax by more or less than your bracket rate.
Allowed range$0 to $10,000,000
We lived apart all year
Tick it if you file separately and did not live with your spouse at any time during the year.
How this tool treats itYou are then treated as not married for both income limits, so the single ranges apply instead of the $0 to $10,000 range.
Your spouse’s taxable compensation
Your spouse’s pay for work for the year, if you file jointly.
Where to find itThe same lines as yours: wages and net self-employment earnings.
How this tool treats itWhen you file jointly and earn less than your spouse, your limit uses your compensation plus your spouse’s, less your spouse’s own IRA contributions. A spouse with little or no pay can contribute this way.
Allowed range$0 to $10,000,000
Your spouse’s own IRA contributions for the year
What your spouse contributes to their own IRAs for the year: traditional and Roth, deductible or not.
How this tool treats itTaken off your spouse’s compensation before it counts toward your limit.
Allowed range$0 to $100,000
After-tax basis already in your traditional IRAs
The nondeductible contributions from earlier years still in your traditional IRAs, not yet taken out or converted.
Where to find itLast year’s Form 8606, line 14.
How this tool treats itA nondeductible contribution is money you put in a traditional IRA without deducting it. It becomes basis, which comes out tax-free in the same proportion as it bears to all your traditional IRA money. A backdoor’s contribution adds to it, and the conversion uses part of it.
Allowed range$0 to $10,000,000
Tax rate on your traditional IRA withdrawals in retirement
The share of each pretax dollar you withdraw that goes to federal and state tax.
How this tool treats itOne rate stands for all your withdrawals: the pretax value times one minus this rate is what a traditional IRA leaves after tax, and after-tax basis comes out tax-free. Roth withdrawals are taken as qualified, so tax-free. The comparison also shows the rate at which the two come out even.
Allowed range0% to 50%
Not includedRequired minimum distributions, early withdrawals and the 10% additional tax.
Tax rate on investment gains
The tax rate on the gain in a taxable investment account when you sell, federal and state together.
How this tool treats itThe comparison puts both routes at the same cost to you now: whichever costs less this year invests the difference in a taxable account, and its gain is taxed once at this rate when you retire.
Allowed range0% to 40%
Not includedYearly tax on the account’s dividends and interest.
State income tax rate
Your state’s income tax rate on your top dollars of income, which is the rate this extra income would be taxed at. Leave it at 0 to leave state tax out.
Where to find itYour state’s rate table for your filing status, at your income. It is usually higher than your average rate, which is last year’s state tax divided by your income.
How this tool treats itApplied to the traditional IRA deduction and to the backdoor conversion’s taxable part, each rounded to the cent, unless you answer no to the two questions below it.
Allowed range0% to 15%
My state lets me deduct IRA contributions
Leave it ticked if your state allows the traditional IRA deduction you take on your federal return.
Where to find itYour state’s income tax instructions.
How this tool treats itUntick it and your state rate is not applied to the deduction.
My state taxes IRA conversions
Leave it ticked if your state taxes the taxable part of a Roth conversion.
Where to find itYour state’s income tax instructions.
How this tool treats itUntick it and your state rate is not applied to the backdoor conversion’s taxable part.
Show in today’s dollars
Turn on to show future figures in today’s dollars.
How this tool treats itA future figure is divided by the rise in prices from now to then at the inflation rate you enter, rounded once to the cent.
Inflation
The yearly rise in prices you expect.
How this tool treats itUsed only for today’s dollars.
Allowed range0% to 10%
Questions
What are the Roth IRA income limits for 2026?
Can I contribute to a Roth IRA if I have a 401(k)?
Is a backdoor Roth allowed?
Why does money in my traditional IRAs make a backdoor taxable?
Should I choose Roth or traditional?
Can I still contribute for last year?
What happens if I put in too much?
Version history
- October 31, 2026 (version 1.0.0): First version: Roth IRA limits by income and filing status, the traditional IRA deduction, a backdoor Roth with Form 8606’s pro-rata rule, and Roth vs traditional at the same cost.