IRA Calculator: Roth vs. Traditional IRA Comparison
The IRA calculator projects the future value of Individual Retirement Account contributions under Traditional and Roth structures, compares after-tax outcomes under each type, and shows the long-term impact of annual contribution limits on retirement wealth. Individuals without employer-sponsored plans, high earners evaluating backdoor Roth strategies, and workers supplementing a 401(k) with additional tax-advantaged savings use this tool. Key outputs include projected balance at retirement, total tax savings in a Traditional IRA, total tax-free growth in a Roth IRA, and the break-even comparison between the two account types. The right IRA type depends on whether your current marginal rate is higher or lower than your expected retirement rate — a question this calculator makes concrete.
This calculator is for educational and informational purposes only. Results are estimates based on the inputs provided and do not constitute financial, tax, legal, or investment advice. Consult a qualified financial professional before making any financial decisions.
How This Calculator Works
For a Traditional IRA, the calculator takes your annual contribution (up to the IRS limit: $7,000 in 2024, $8,000 if 50+), applies your marginal tax rate to find the actual after-tax cost of the contribution, then projects the balance forward at the assumed return rate. At withdrawal, it applies your estimated retirement tax rate to show the after-tax distribution amount. For a Roth IRA, contributions are after-tax (no immediate deduction), but the balance grows and withdraws tax-free. The calculator compares after-tax ending wealth under each type to show which is more valuable for your specific tax situation.
How to Use This Calculator
Enter your current age and planned retirement age.
Enter your annual IRA contribution (up to 2025 limit of $7,000).
Enter your current IRA balance.
Set your expected annual return in Advanced Inputs.
Enter your current and expected retirement tax rates for the Roth vs. Traditional comparison.
Enable the catch-up contribution toggle if you are age 50 or older.
Review Roth vs. Traditional after-tax values to determine the better option.
Formula
Traditional IRA After-Tax Balance = FV × (1 − Retirement Tax Rate). Roth IRA Balance = FV (fully tax-free). FV = Annual Contribution × [(1+r)^n − 1] ÷ r. After-Tax Cost of Traditional Contribution = Contribution × (1 − Current Marginal Rate). Roth wins when Retirement Tax Rate > Current Marginal Rate; Traditional wins in the reverse.
After-Tax Comparison
Roth After-Tax = FV (no tax on withdrawal). Traditional After-Tax = FV × (1 − retirement tax rate)Where:
- FV
- Future value at retirement using same growth rate for both accounts
- Retirement Tax Rate
- Expected marginal rate when withdrawing from Traditional IRA
Example
Roth FV = $400,000 (all tax-free). Traditional FV = $400,000 × (1−0.22) = $312,000 after-tax. Roth wins if retirement rate ≥ current rate.
Step-by-Step Example
Suppose you are 30, contribute $7,000 per year to an IRA, expect 7% returns, and plan to retire at 65 in the 22% current bracket with a projected 20% retirement bracket.
- 1FV = $7,000 × [(1.07)^35 − 1] ÷ 0.07 = $7,000 × 138.24 = $967,700
- 2Traditional IRA: deduction saves $7,000 × 22% = $1,540/year in taxes; balance at retirement = $967,700
- 3Traditional after-tax distribution value = $967,700 × (1 − 0.20) = $774,160
- 4Roth IRA: no upfront deduction; after-tax cost = $7,000 × (1 − 0.22) = $5,460/year effective
- 5Roth balance at retirement = $967,700 (fully tax-free)
- 6Roth advantage = $967,700 − $774,160 = $193,540 in additional after-tax wealth
Roth IRA after-tax balance: $967,700 vs. Traditional after-tax: $774,160 — Roth wins by $193,540
Because the current rate (22%) equals the retirement rate (20%), the Roth wins due to the rate differential. If the retirement rate were 24%, the Traditional would produce higher after-tax wealth. The higher the expected future tax rate relative to today's rate, the stronger the case for Roth contributions.
Understanding Your Results
The after-tax comparison reveals which IRA type is more valuable for your specific tax situation. The Traditional wins when you expect to be in a lower bracket in retirement; the Roth wins when you expect to be in the same or higher bracket. Required minimum distributions (beginning at age 73) apply to Traditional IRAs but not Roth IRAs, adding flexibility for estate planning. If your income is too high for direct Roth contributions ($161,000 single / $240,000 married in 2024), the backdoor Roth strategy may still allow after-tax Roth accumulation.
Factors That Affect Your Result
Current vs. Retirement Marginal Rate Differential
The magnitude of the tax rate difference between today and retirement determines how large the advantage is for the winning account type. A 10-percentage-point rate reduction in retirement creates a strong Traditional IRA case; a rate increase creates a strong Roth case.
Required Minimum Distribution Impact
Traditional IRA holders must take RMDs starting at 73, which can push retirement income into higher brackets and increase Medicare premiums. Roth IRAs have no RMDs, preserving flexibility to defer withdrawals and reduce lifetime tax exposure.
Estate Planning Considerations
Roth IRAs pass to heirs income-tax-free and can be stretched over 10 years under current law. Traditional IRA heirs owe income tax on all distributions. For accounts intended to be inherited, the after-tax value to heirs differs substantially between account types.
Income Phaseout Ranges for Deductibility
Traditional IRA deductibility phases out for covered workplace plan participants at $77,000–$87,000 (single) and $123,000–$143,000 (married) in 2024. Above these limits, Traditional contributions are non-deductible and should generally be converted via backdoor Roth instead.
State Tax Treatment
Some states exempt retirement income from state income tax entirely; others tax all distributions. A Traditional IRA contribution that saves 6% state income tax today may produce a taxable distribution in a state with no retirement income exemption, reducing the Traditional advantage.
Common Mistakes to Avoid
Not Contributing Because of Income Limits
High earners above the Roth income limit can use the backdoor Roth strategy: make a non-deductible Traditional IRA contribution and then convert it to Roth. This strategy is legal and widely used but requires careful execution to avoid the pro-rata rule.
Choosing Traditional Due to Immediate Deduction Without Modeling Retirement Tax
The deduction feels good today, but if your retirement income from pensions, Social Security, and RMDs pushes you into the 22–24% bracket, the Traditional deduction did not actually save taxes — it only deferred them.
Missing the Contribution Deadline
IRA contributions for a tax year can be made through the tax filing deadline (April 15 of the following year). Missing this window permanently forfeits that year's contribution room, which cannot be carried forward.
Investing IRA Funds in Cash or Low-Return Products
An IRA is a tax-advantaged wrapper, not an investment. Leaving IRA funds in the default money market position rather than investing them in diversified index funds wastes the tax shelter on minimal growth.
Exceeding the Contribution Limit
Contributing more than the annual limit triggers a 6% excise tax on the excess each year until it is removed. Tracking contributions across all IRA accounts — Traditional and Roth — is essential since the limit applies to combined contributions.
Advanced Tips
Execute Roth Conversions in Low-Income Years
Years with unusually low income — job change gap, early retirement before Social Security, major deductions — are ideal for Roth conversions. Converting Traditional to Roth at a 12% rate avoids future distributions at a potentially higher rate.
Use the Backdoor Roth if Income Exceeds Limits
Contribute to a non-deductible Traditional IRA and convert immediately to Roth before any earnings accrue. Keep the Traditional IRA balance at zero otherwise to avoid the pro-rata rule taxing a portion of the conversion.
Coordinate IRA Withdrawals with Social Security Timing
Delaying Social Security to 70 while drawing from a Traditional IRA in your 60s keeps total income lower in early retirement, potentially reducing the taxable portion of future Social Security benefits and Medicare premium surcharges.
When to Consult a Professional
Consult a CFP or CPA when considering Roth conversions above $50,000, when implementing a backdoor Roth with existing Traditional IRA balances (pro-rata rule complexity), when you have inherited an IRA and face the 10-year distribution rule, or when coordinating IRA withdrawals with Social Security timing to minimize lifetime taxes.
Authoritative Resources
External links are provided for informational purposes. FinCalc Pro does not endorse or have an affiliation with any third-party organizations listed below.
- Internal Revenue Service
IRS: Individual Retirement Arrangements (IRAs)
IRS comprehensive guide to IRA types including traditional, Roth, SEP, and SIMPLE IRAs with contribution and deduction rules.
- Internal Revenue Service
IRS: Roth IRAs
IRS guidance on Roth IRA contribution limits, income phase-out ranges, and qualified distribution rules.
- Internal Revenue Service
IRS: IRA Deduction Limits
Current-year traditional IRA deductibility rules based on income, filing status, and workplace plan participation.
- Internal Revenue Service
IRS: Retirement Topics – Required Minimum Distributions (RMDs)
IRS rules on when and how much you must withdraw from traditional IRAs annually once you reach RMD age.
- U.S. Securities and Exchange Commission – Investor.gov
SEC Investor.gov: Roth IRA
SEC investor education on Roth IRA benefits, eligibility, and how tax-free growth works over time.