Backdoor Roth IRA Calculator
Determine if a backdoor Roth IRA conversion makes sense for you. Check for pro-rata rule issues and calculate the tax impact.
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This calculator is for informational and educational purposes only. Results are estimates based on the information you provide and standard financial formulas. This is not financial advice. Consult a qualified financial advisor for decisions specific to your situation. Full Disclaimer
Advanced Backdoor Roth Analysis PRO-RATA
⌄Personalized Backdoor Roth analysis appears after you Calculate
Should You Use The Backdoor Roth Strategy?
The Backdoor Roth is a legal workaround for high earners blocked from direct Roth IRA contributions. You contribute non-deductible $7,500 to a Traditional IRA, then immediately convert it to Roth. The IRS has explicitly affirmed this strategy in IRS Notice 2018-69 and TCJA legislative history. But it ONLY makes sense in specific circumstances.
| Your Situation | Backdoor Roth? | Why |
|---|---|---|
| Income below Roth phase-out | No — just contribute directly | You can contribute directly. No backdoor needed. |
| Income above Roth phase-out, NO other Trad IRA balance | YES — clean backdoor | $7,500 contribution converted tax-free (basis recovery) |
| Income above + has pre-tax Trad IRA balance | Pro-rata trap — see Tab 2 | Pro-rata rule makes most of conversion taxable |
| Self-employed with SEP-IRA or SIMPLE | Pro-rata trap applies | SEP-IRA + SIMPLE-IRA balances count toward pro-rata calculation |
| 401(k) plan accepts rollovers FROM IRA | Reverse-roll first, then YES | Move pre-tax IRA to 401(k), then do clean backdoor |
2026 income thresholds — when do you NEED the backdoor?
| Filing Status | Direct Roth Allowed Below | Backdoor Required Above |
|---|---|---|
| Single / HOH | $153,000 (full) | $168,000 (no direct contribution) |
| Married filing jointly / QSS | $242,000 (full) | $252,000 (no direct contribution) |
| MFS — lived together | $0 (statutory) | $10,000 (no direct contribution) |
If you're between the lower and upper threshold (in the phase-out), you can do a partial direct Roth + partial backdoor for the remainder. Example: single with $160K MAGI ($7K into the $15K phase-out range) can contribute ~$3,750 directly to Roth + $3,750 via backdoor.
Backdoor Roth strategy explicitly affirmed in Joint Committee on Taxation "General Explanation of Public Law 115-97" (2017 TCJA) at p. 289 and IRS Notice 2018-69. Pro-rata rule per IRC §408(d)(2). Step-transaction concern addressed in Kitces analysis 2018.
The Pro-Rata Rule — The #1 Backdoor Roth Trap
If you have ANY pre-tax dollars in Traditional IRAs (including SEP-IRA and SIMPLE-IRA), the IRS treats them all as one pool when you do a Backdoor Roth conversion. You cannot just "convert the non-deductible $7,500" — the IRS considers your conversion to be a proportional mix of basis (after-tax) and pre-tax dollars from your entire IRA aggregate.
| Total IRA dollars after contribution | $100,000 |
| Basis (non-deductible / after-tax) | $7,500 (7.5%) |
| Pre-tax (taxable on conversion) | $92,500 (92.5%) |
| Tax-free portion of $7,500 conversion | ~$562 |
| Taxable portion of conversion | ~$6,938 |
| Tax cost on this conversion | ~$2,220 |
3 ways to escape the pro-rata trap
1. Reverse-rollover to 401(k) ⚙
Most 401(k) plans accept incoming rollovers from IRAs. Roll your pre-tax Trad IRA balance INTO your 401(k), leaving only the non-deductible basis in the IRA. Then do clean backdoor conversion. Most common solution.
2. Solo 401(k) (self-employed) $$
If you have any self-employment income, set up a Solo 401(k). Roll SEP-IRA and pre-tax Trad IRA balances into the Solo 401(k). Then do clean backdoor.
3. Convert and accept the tax ×
If you have a small pre-tax balance, you can convert ALL of it to Roth in one tax year. Pay the full tax bill, then have a $0 pre-tax balance going forward — clean for future backdoors.
Pro-rata rule per IRC §408(d)(2). Calculation per Form 8606 Worksheet 1-1 (IRS Pub 590-B). The Dec 31 timing rule per Pub 590-B Worksheet 1-1 instructions. Reverse-rollover acceptance varies by plan — check with your 401(k) administrator.
Form 8606 — The Form You CANNOT Skip
Every year you make a non-deductible Traditional IRA contribution, you MUST file Form 8606 with that year's tax return. This establishes your "basis" — the after-tax dollars in your IRAs. Without Form 8606, the IRS treats every withdrawal as fully taxable, and you'll pay double tax on the same dollars.
| Form 8606 Triggers — File If You... | Why It Matters |
|---|---|
| Made a non-deductible Traditional IRA contribution | Establishes your basis (line 1) |
| Did a Backdoor Roth conversion | Reports the conversion + basis recovery |
| Took a distribution from a Trad IRA with basis | Calculates taxable vs nontaxable portion via pro-rata |
| Inherited an IRA with basis | Track inherited basis separately |
| Did any Roth conversion (even non-backdoor) | Reports the conversion amount |
What Form 8606 looks like for a clean backdoor
| Line | Field | Backdoor Scenario Value |
|---|---|---|
| Line 1 | Non-deductible contributions for 2026 | $7,500 |
| Line 2 | Total basis from prior years | $0 (first time) |
| Line 3 | Total basis (Line 1 + Line 2) | $7,500 |
| Line 6 | Dec 31 IRA balance (all Trad/SEP/SIMPLE) | $0 (clean backdoor) |
| Line 8 | Amount converted to Roth in 2026 | $7,500 |
| Line 13 | Basis applied to conversion (% of Line 8) | $7,500 (100%) |
| Line 18 | Taxable conversion amount | $0 ✓ tax-free |
Recordkeeping — keep forever
Keep every Form 8606 you've ever filed permanently. Not just 7 years like other tax records — these prove your basis decades into the future when you start withdrawing. Most custodians do NOT track basis for you. The IRS does NOT track it for you. You are solely responsible. Store digital copies in cloud storage with multiple backups. Print extras for your file.
Form 8606 instructions: IRS Form 8606. Penalty per IRC §6693. Recordkeeping responsibility per Pub 590-A page 22. Inherited IRA basis tracking per IRS Notice 87-16 and Pub 590-B.
Mega Backdoor Roth — The High-Earner Power Move (Up to $46,500/year)
If your 401(k) plan supports it, the Mega Backdoor Roth lets you contribute up to $46,500 of after-tax dollars to your 401(k) and convert them to Roth annually — far more than the $7,500 IRA Backdoor. Two requirements: (1) plan allows after-tax contributions, AND (2) plan allows in-service distributions OR in-plan Roth conversions.
| 2026 401(k) Cap Layer | Amount | Roth Treatment? |
|---|---|---|
| 1. Employee elective deferral (Roth or Trad) | $24,500 | Your election |
| 2. Catch-up if 50+ | $8,000 | Roth required if $150K+ wages |
| 3. Super catch-up if 60-63 | $11,250 | Roth required if $150K+ wages |
| 4. Employer match/profit-share | Variable | Pre-tax (typically) |
| 5. Voluntary after-tax contributions (Mega Backdoor) | Fills to $70K total cap | After-tax → convert to Roth |
| Total §415(c) cap | $70,000 (or $77,500 at 50+) | — |
Plan requirements — most plans don't support this
- After-tax contribution allowed. Different from Roth. Most plans don't have this option. Ask plan admin.
- In-service distribution OR in-plan Roth conversion. Without this, the after-tax dollars sit in the plan accumulating taxable earnings. The conversion path is needed to keep growth tax-free.
- Plan tracks contribution sources separately. Critical for Mega Backdoor — the conversion is only on the after-tax basis, NOT pre-tax dollars.
- Best plans for Mega Backdoor: Tech companies (Microsoft, Google, Meta, Amazon, Salesforce), some big banks (Goldman, JPM), some accounting firms.
Frequency — convert often
After-tax dollars in the 401(k) accumulate taxable earnings until converted. Convert as frequently as your plan allows — ideally each pay period or at minimum quarterly. The longer you wait, the more pre-tax growth gets mixed in, creating its own pro-rata complication on the conversion.
§415(c) total contribution cap of $70,000 for 2026 per IRS Notice 2025-67. Mega Backdoor strategy per Treas. Reg. §1.402A-1, Q&A-5. After-tax 401(k) contributions distinct from Roth contributions per §402A. Kitces 2014 analysis first popularized the term "Mega Backdoor Roth."
Annual Timing — Step-By-Step Backdoor Process
Execute your Backdoor Roth on a clean schedule each year. The process below is the standard sequence; deviation creates tax complications.
| Step | Action | Timing |
|---|---|---|
| 1. Verify pre-tax IRA balance is $0 | Check Trad/SEP/SIMPLE accounts. If non-zero, address pro-rata first (reverse-rollover to 401k). | Before contribution |
| 2. Make non-deductible Trad contribution | Contribute $7,500 ($8,600 if 50+) to Traditional IRA. Use cash, not appreciated stock. | Jan 1 - Apr 15 of following year |
| 3. Wait briefly | 1 day to 1 week recommended (no legal requirement). Establishes separate transactions. | 1-7 days |
| 4. Convert to Roth IRA | Direct conversion via custodian (Vanguard, Fidelity, Schwab all support). Convert full $7,500. | Same calendar year |
| 5. Confirm $0 earnings on conversion | If small earnings accrued (e.g., $5 interest), convert those too. Earnings are taxable. | At conversion |
| 6. File Form 8606 with tax return | Reports the non-deductible contribution AND the conversion. Both events on same form. | By Apr 15 of following year |
| 7. Verify 1099-R received Jan-Feb | Custodian sends 1099-R for the conversion. Code 2 (early distribution, exception applies) for under 59½, code 7 for over 59½. | January - February of following year |
| 8. Repeat next year | Same process every year. Many high earners automate via custodian's "automatic conversion" feature. | Annually |
- January: Verify $0 pre-tax balance. If your 401(k) accepts rollovers, set up reverse-rollover for any pre-tax IRA balances.
- February: Contribute $7,500 to Traditional IRA. Keep in cash (money market).
- February-March: Convert to Roth IRA (1-7 days after contribution).
- April: File Form 8606 with your tax return.
- December: Confirm $0 pre-tax IRA balance for year-end pro-rata test.
Common pitfalls to avoid
- Don't claim the deduction. Your $7,500 Traditional contribution is intentionally non-deductible. If your tax software auto-deducts it, manually override on Form 8606.
- Don't invest in Trad IRA before converting. Keep in money market/cash. Earnings before conversion become taxable on conversion.
- Don't do partial conversions. Convert the full $7,500. Partial conversions complicate basis tracking.
- Don't trigger the 60-day rollover rule. Use direct trustee-to-trustee transfer for the conversion, not a "60-day rollover" — those have once-per-year limits.
- Watch for state tax surprises. Most states tax the conversion as ordinary income. Some (CA, NJ) have specific quirks.
Backdoor Roth process detailed in IRS Notice 2018-69 and Pub 590-B. The "no waiting period" rule confirmed in TCJA legislative history. State tax treatment varies — see state-specific guidance from AICPA and state revenue departments.
Continue your high-income retirement strategy
Things to Know
Essential concepts for understanding your results
How It WorksWhat is a backdoor Roth IRA conversion?
A backdoor Roth lets high earners bypass the income limits by contributing to a traditional IRA (no income limit for non-deductible contributions) then immediately converting to a Roth IRA. The conversion triggers tax only on any growth between contribution and conversion — if converted quickly, the tax is near zero. This two-step process is fully legal and explicitly acknowledged by the IRS.
Pro-Rata RuleWhat is the pro-rata rule and how does it affect you?
If you have any pre-tax IRA balances (traditional, SEP, or SIMPLE), the IRS treats all IRAs as one pool for tax purposes. A conversion is taxed proportionally across pre-tax and after-tax balances. With $90,000 pre-tax and $7,500 after-tax: only 7.2% of the conversion is tax-free. Solution: roll pre-tax IRA balances into your employer 401(k) before converting, leaving only after-tax money in the IRA.
Mega BackdoorWhat is a mega backdoor Roth?
The mega backdoor Roth uses after-tax 401(k) contributions above the $24,500 employee limit (up to the $69,000 total limit) then converts to Roth. This allows $30,000-45,000+ in additional Roth contributions annually — far beyond the $7,500 IRA limit. Requires a 401(k) plan that allows after-tax contributions and in-plan Roth conversions. Check with your HR department for plan provisions.
TimingWhen should you do a backdoor Roth conversion?
Execute both steps — contribution and conversion — as close together as possible, ideally the same day or within a few days. This minimizes any taxable growth. Do it early in the year to maximize time for tax-free Roth growth. Avoid converting during years with unusually high income, as any taxable portion is added to your marginal rate. January is the optimal month for annual backdoor Roth conversions.
Backdoor Roth IRA Calculator: Tax-Free Retirement Savings for High Earners
The backdoor Roth IRA is a legal strategy for high-income earners to contribute to a Roth IRA despite exceeding the income limits. In 2026, direct Roth IRA contributions are phased out for single filers above $153,000 MAGI and joint filers above $242,000. The backdoor circumvents these limits through a two-step process that the IRS has explicitly acknowledged as permissible.
Enter your income, filing status, and existing Traditional IRA balances above. The calculator shows whether you qualify for direct Roth contributions, need the backdoor strategy, and estimates the tax-free growth over your investment horizon.
How the Backdoor Roth Works: Step by Step
Step 1: Contribute $7,500 ($8,000 if 50+) to a Traditional IRA — non-deductible (since your income is too high for deduction if you have an employer plan). No income limit on non-deductible Traditional IRA contributions.
Step 2: Convert the Traditional IRA to a Roth IRA. Since you just contributed after-tax money, the conversion is tax-free (you already paid tax on the contribution). File Form 8606 with your tax return to document the non-deductible basis.
Critical warning — the Pro-Rata Rule: If you have ANY existing pre-tax Traditional IRA balance (from prior deductible contributions or rollovers), the conversion is NOT tax-free. The IRS uses the pro-rata rule: the taxable percentage of your conversion = (pre-tax IRA balance) ÷ (total IRA balance). With $93,000 pre-tax + $7,500 non-deductible contribution: 93% of the $7,500 conversion is taxable. Solution: roll all pre-tax IRA money into your 401(k) before the conversion — leaving only the non-deductible contribution in the IRA.
Mega backdoor Roth (employer plan dependent): Some 401(k) plans allow after-tax contributions above the $24,500 employee limit, up to the total 415(c) limit of $70,000 (2026, including employer match). These after-tax 401(k) contributions can be converted to Roth (in-plan or rollover). This allows $40,000-$46,000+ in additional Roth savings per year — the most powerful Roth strategy available.
Frequently Asked Questions
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How to Use This Calculator
Enter your income, filing status, and existing Traditional IRA balance. The calculator shows whether you qualify for direct Roth IRA contributions, need the backdoor strategy, and models the tax impact of the conversion. The critical input is your existing Traditional IRA balance — if it is above zero, the pro-rata rule applies and makes the conversion partially taxable.
Example: A single filer earning $160,000 exceeds the Roth IRA income limit ($153,000 phase-out in 2026). They contribute $7,500 to a non-deductible Traditional IRA, then immediately convert to Roth. With zero existing Traditional IRA balance, the conversion is tax-free. With a $50,000 existing Traditional IRA balance, approximately $6,140 of the $7,500 conversion would be taxable due to the pro-rata rule.
The Backdoor Roth IRA: Step-by-Step Process
The backdoor Roth is not a special account type — it is a two-step strategy that allows high earners to fund a Roth IRA despite income limits. Here is exactly how to execute it:
Step 1: Contribute to a Traditional IRA. If your income exceeds the deduction limits, this contribution is non-deductible (you do not get a tax break). The 2026 limit is $7,500 ($8,000 if age 50+).
Step 2: Convert the Traditional IRA to a Roth IRA. There are no income limits on conversions. If the account only contains non-deductible contributions (and has not earned significant investment gains), the conversion is tax-free or nearly so.
Step 3: File IRS Form 8606 with your tax return to report the non-deductible contribution and the conversion. This is the step most people forget — without Form 8606, the IRS may treat your conversion as fully taxable.
Timing tip: Convert as quickly as possible after contributing — ideally the same day or next business day. This minimizes any investment gains in the Traditional IRA, which would be taxable upon conversion.
The Pro-Rata Rule: The Critical Trap
The pro-rata rule is the most common mistake in backdoor Roth conversions. If you have any existing pre-tax money in any Traditional, SEP, or SIMPLE IRA, the IRS treats all your IRA money as one pool. You cannot convert just the non-deductible portion — the conversion is prorated across all IRA assets.
| Existing Traditional IRA | $7,500 conversion | Taxable portion | Tax cost (24% bracket) |
|---|---|---|---|
| $0 (ideal) | $7,500 | $0 (100% non-deductible) | $0 |
| $20,000 | $7,500 | $5,185 (74% taxable) | $1,244 |
| $50,000 | $7,500 | $6,140 (88% taxable) | $1,474 |
| $100,000 | $7,500 | $6,542 (93% taxable) | $1,570 |
The fix: Roll your existing Traditional IRA into your employer 401(k) before doing the backdoor conversion. Most 401(k) plans accept incoming IRA rollovers. This zeros out your IRA balance and makes the backdoor conversion completely tax-free. This is the most important preparatory step and the one most articles do not emphasize enough.
Mega Backdoor Roth: The Advanced Strategy
If your 401(k) plan allows after-tax contributions and in-service distributions, you can contribute up to $69,000 total (2026 combined limit including employer match and after-tax) and convert the after-tax portion to Roth — far exceeding the $7,500 backdoor IRA limit. Not all plans offer this, but if yours does, it is the most powerful Roth funding strategy available. Check with your HR department or plan administrator for eligibility.