Free backdoor roth ira calculator
Over the Roth income limit? Project what a non-deductible-then-converted backdoor Roth grows into, 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 backdoor Roth IRA?
A backdoor Roth IRA is a two-step move that lets high earners fund a Roth IRA even though their income is above the limit for contributing to one directly. You make a non-deductible contribution to a traditional IRA, then convert it to a Roth shortly after. Because there is no income limit on conversions, this is the legal back door into a Roth for people the front door is closed to. This backdoor Roth IRA calculator projects what those annual contributions grow into over time.
The whole strategy exists because of one threshold. In 2025 the ability to contribute to a Roth IRA directly phases out at $150,000–$165,000 of modified AGI for single filers and $236,000–$246,000 for married couples filing jointly. Above the top of your range, a direct Roth contribution is barred — and the backdoor is how high earners get in anyway.
How the backdoor Roth works, step by step
- Contribute to a traditional IRA. Put in up to the annual limit ($7,000 in 2025, $8,000 if 50 or older) as a non-deductible contribution. There is no income limit on making a non-deductible traditional contribution.
- Convert to a Roth IRA. Soon after — typically once the cash settles — convert the balance to a Roth. There is no income limit on conversions.
- Report it on Form 8606. File Form 8606 to record the non-deductible basis and show the conversion. Done cleanly, almost none of the conversion is taxable because you already paid tax on the contribution.
The pro-rata trap that breaks a backdoor Roth
The backdoor Roth only stays tax-free if your traditional IRAs hold no other pre-tax money. The IRS pro-rata rule treats every dollar across all your traditional, SEP, and SIMPLE IRAs as a single pool, measured on December 31. You cannot convert just the after-tax dollars — the conversion is taxable in the same proportion that pre-tax money makes up the whole pool. A single old rollover IRA can turn a "tax-free" backdoor into a mostly taxable one.
| Situation (Dec 31) | Pre-tax IRA | Backdoor $7,000 basis | Taxable on conversion |
|---|---|---|---|
| No other IRA money (clean) | $0 | $7,000 | $0 — fully tax-free ✓ |
| $50,000 rollover IRA sitting there | $50,000 | $7,000 | ≈ $6,140 taxable (88%) |
| $140,000 rollover IRA sitting there | $140,000 | $7,000 | ≈ $6,667 taxable (95%) |
Pro-rata applies to ALL your IRAs at year-end. This calculator projects growth only — it does not compute pro-rata tax. Figure the taxable share on Form 8606.
IRS — About Form 8606, Nondeductible IRAs (figures the taxable portion of a conversion).How to use the backdoor Roth calculator
This calculator does not model the tax — that depends on your pro-rata situation. What it does is project the long-term growth of contributing the backdoor amount every year, so you can see why even the modest IRA limit compounds into real money.
- Annual contribution. The amount you put in each year — the 2025 IRA limit is $7,000, or $8,000 if you are 50 or older.
- Years contributing. How many years you keep doing the backdoor Roth.
- Expected return. The average annual growth rate you assume for the Roth.
A worked example: $7,000 a year for 20 years
Marcus earns too much to contribute to a Roth directly, so each year he does a clean backdoor Roth: $7,000 in, converted right away. He keeps it up for 20 years and assumes a 7% return. To reproduce this, set Annual contribution = 7000, Years = 20, Expected return = 7.
Step 1 — Contribute and convert each year
Because his only IRA money is the fresh backdoor contribution, the pro-rata fraction is zero and each conversion is tax-free. Over 20 years he contributes $140,000 total.
Step 2 — Let it compound tax-free
2025 backdoor Roth limits and thresholds
| Item (2025) | Figure | Notes |
|---|---|---|
| IRA contribution limit (under 50) | $7,000 | The most a single year's backdoor moves. |
| IRA catch-up (age 50+) | +$1,000 | Total $8,000 for those 50 or older. |
| Roth income phase-out (single) | $150,000–$165,000 MAGI | Above this, direct Roth is barred — use the backdoor. |
| Roth income phase-out (MFJ) | $236,000–$246,000 MAGI | The married threshold. |
| Income limit on conversions | None | What makes the backdoor legal. |
2025 figures published by the IRS. The backdoor Roth is capped by the same IRA contribution limit as any other IRA.
IRS — 401(k) limit increases to $23,500 for 2025; IRA limit $7,000, Roth phase-out ranges for 2025.Who should use a backdoor Roth IRA
- High earners over the Roth income limit who still want Roth dollars and have no pre-tax IRA balances to trip the pro-rata rule.
- Anyone with a clean IRA picture — no traditional, SEP, or SIMPLE IRA balances, because employer-plan money is rolled into a 401(k) or never left there.
- Savers who have maxed their 401(k) and want an extra $7,000–$8,000 of tax-advantaged space each year.
If you have a large pre-tax IRA you cannot easily roll into a 401(k), the pro-rata rule may make the backdoor too costly. In that case the mega backdoor Roth — which works inside a 401(k) and avoids IRA pro-rata entirely — is often the better path.
Backdoor Roth gotchas
- Holding a pre-tax IRA at year-end. The number-one mistake. Roll pre-tax IRA money into an employer 401(k) before December 31 to zero out the pro-rata base.
- Skipping Form 8606. Without it the IRS has no record of your after-tax basis, and you risk being taxed twice on the same money.
- Deducting the contribution. The traditional contribution must be non-deductible. Deduct it and the conversion becomes fully taxable.
- Letting it grow before converting. Any earnings between contribution and conversion are taxable. Convert promptly to keep the taxable piece near zero.
- Confusing it with the mega backdoor. The backdoor Roth is an IRA move capped at $7,000–$8,000; the mega backdoor is a 401(k) move that can move far more.
Accuracy, assumptions, and sources
This backdoor Roth IRA calculator projects the future value of equal annual contributions at a fixed return; it assumes a clean conversion with no pro-rata tax. It does not model the pro-rata rule, taxes, fees, or variable returns. The strategy's tax outcome depends entirely on your year-end IRA balances and is reported on Form 8606. Treat the result as a planning estimate, not tax advice, and confirm your situation with a CPA. Verify current limits on IRS.gov.
IRS — Roth IRAs (contributions, conversions, and income limits).IRS — Amount of Roth IRA contributions you can make (income phase-out mechanics).Frequently asked questions about the free backdoor roth ira calculator
About this backdoor Roth IRA calculator
This calculator projects the long-term, tax-free growth of an annual backdoor Roth — a non-deductible traditional IRA contribution converted to a Roth — the workaround high earners use when their income is above the direct Roth limit. It also explains the pro-rata rule that decides whether the conversion stays tax-free.
Find it among our retirement calculators, or explore the rest of the site from the full calculator directory. Limits are 2025 IRS figures; results are estimates, not tax advice.