401(k) & IRA calculator
Compare four tax-advantaged account types in one projection. The model keeps Roth and pre-tax balances separate so it can estimate taxes, after-tax value, and required distributions.
What should be calculated
Advanced options
Contribution timeline
Account value by age
Scenario comparison
If you contributed more
How after-tax retirement value changes as the contribution rate moves from zero through the annual-limit plateau.
Retirement assets by tax status
Projected Roth, tax-deferred, and taxable balances through retirement.
Contribution-limit headroom
Separate room under the employee-deferral and total-additions limits. The published 2026 limits are $24,500 and $72,000; later rows are estimates based on IRS guidance.
Roth–traditional comparison
Tax-rate crossover
How Roth minus traditional retirement value changes with the future tax-rate assumption, at equal personal cost.
Required minimum distributions
Return sensitivity
What the account is worth at the end at each return in the range you chose. The banded column is your return.
Annual projection
What this model assumes
- The return and the salary rise by the same percentage every year. Neither does in practice, and the order returns arrive in changes the answer.
- Tax is one flat rate on each side: the rate a contribution saves now, and the rate the whole deferred balance pays on the way out. Nothing here models brackets, the order money comes out in, state tax, or a year spent in a lower band.
- Contribution limits use the published 2025 and 2026 statutory schedules, including age-50 and workplace age-60–63 catch-ups, eligible-compensation and annual-additions ceilings. The model uses projected salary as a proxy for prior-year FICA wages when applying the 2026 mandatory Roth catch-up source above the wage threshold. Later unpublished years are estimates indexed by the inflation entered. A 401(k) and Roth 401(k) share one elective-deferral limit, as do the two IRAs; verify the current IRS limits.
- In the comparison, the tax a deferred contribution saves is invested beside it in a taxable account whose growth is taxed as it is earned, so both plans cost the same out of pocket — and the gap at equal tax rates is precisely what that tax drag costs. Whatever is already saved stays where it is: moving it to Roth would be a separate conversion with potential tax consequences.
- Required distributions use the IRS Uniform Lifetime Table, with a modeled age of 73 for people born from 1951 through 1959 and 75 from 1960 onward. Traditional IRAs begin at that legal age. A workplace plan delays until retirement only when the still-working option is on; turn it off for a 5% owner or a plan that requires an earlier start. They apply only to money this model treats as never taxed. Employer match is modeled as tax-deferred unless entered as an existing Roth source; verify the account, plan, and current IRS guidance.
- Not modelled: income limits on Roth IRA contributions or on deducting a traditional one, the after-tax and mega-backdoor routes, loans, early-withdrawal penalties, or an inherited account. These projections are informational estimates, not personalized financial or tax advice. Tax rules may change. For retirement spending projections, use the Retirement & FIRE calculator.
Calculations are estimates based on your assumptions and are not financial or investment advice. Actual results may differ. Read the financial disclaimer.