Roth IRA vs Traditional 401(k) Calculator
Compares after-tax retirement balance for both account types using your current IRS 2026 marginal rate and your projected retirement rate.
Roth IRA vs Traditional 401(k) Calculator
Compare net spendable retirement balances. Evaluate upfront tax deduction benefits against tax-free compound distributions based on your statutory marginal rate and projected retirement bracket.
Tax Profile & Contribution
2026 IRA Cap: $7,000 ($8,000 age 50+) • 401(k) Deferral: $24,500
Current and projected retirement tax rates are nearly identical. Either account type yields a similar after-tax outcome — prioritize flexibility (Roth) or the current tax deduction (Traditional).
Worked Example — Early-Career vs Peak-Earning Scenarios
Scenario A: Early-Career Filer ($45,000 Income) in the 12% federal marginal bracket contributing $7,000/year over 30 years at 7.0%. If retirement income reaches the 22% bracket, the Roth vehicle provides an immediate mathematical advantage of over $40,000 in net spendable retirement assets.
| Metric | Traditional 401(k) | Roth Account | Variance |
|---|---|---|---|
| Current Contribution Out-of-Pocket | $7,000 pre-tax ($6,160 net cost) | $7,000 after-tax | -$840 upfront |
| Gross Value at Age 65 (7%) | $707,511 | $707,511 | $0 identical |
| Federal Tax Paid at Withdrawal | -$155,652 (at 22%) | $0 (exempt §408A) | +$155,652 |
| Net Spendable Balance | $551,859 | $707,511 | +Roth Wins |
Statutory Framework & Taxation Timelines
Traditional 401(k) and IRA contributions are made with pre-tax dollars under IRC §401(k) and §219, reducing current Adjusted Gross Income (AGI). Withdrawals are treated as ordinary taxable income upon distribution.
Roth contributions are made after income taxes have been paid (IRC §408A). In exchange, all earnings grow tax-free, and qualified withdrawals after age 59½ (with a 5-year holding period) are completely exempt from federal income taxation.
Exclusions & Technical Scope
- Income Phase-Outs: Direct Roth IRA contributions are phased out for high earners ($150,000–$165,000 Single; $236,000–$246,000 Married Joint in 2026). High earners may use backdoor Roth conversions.
- State Income Taxes: State tax rates on retirement distributions vary by jurisdiction (e.g. 9 states have zero income tax).
- Future Tax Bracket Changes: Congressional adjustments to federal statutory brackets over multi-decade time horizons are not forecasted.
Méthodologie de calcul
Calculates current marginal tax bracket from 2026 IRS schedules, projects tax-deductible Traditional contributions versus after-tax Roth growth with tax-free qualified withdrawals.
Identifies mathematical breakeven retirement tax rate, net after-tax spendable balance for each account type, and personalized recommendation.
Frequently Asked Questions (FAQ)
When is a Roth IRA mathematically superior to Traditional?
Roth is superior when your projected marginal tax rate in retirement exceeds your current marginal tax bracket during contribution years.
Are Roth withdrawals entirely tax-free?
Yes, qualified distributions from a Roth account after age 59½ that meet the 5-year aging rule are 100% exempt from federal income tax.
Can high earners contribute to a Roth account?
Direct Roth IRA contributions are phased out for high earners, but backdoor Roth conversions and designated Roth 401(k) plans carry no income caps.