Compare a Roth IRA against a 401k after tax.
On $7,000 a year for 30 years at 7%, roth ira wins by $13,225 after tax. The account grows to $6,61,226 before any retirement tax — and remember, only the 401k earns an employer match.
Calculated in your browser. Compares equal contributions and assumes the traditional's up-front tax saving is invested. Uses flat marginal rates. Not tax advice.
Formulas and content last reviewed . IRS limits change each year — confirm current figures at IRS.gov and with your plan administrator.
The short answer
A Roth IRA is funded with after-tax dollars and grows tax-free; a traditional 401k is pre-tax now and taxed on withdrawal. The 401k almost always wins first because of the employer match — free money the IRA can't offer. Beyond the match, a Roth IRA's tax-free growth and flexibility often win if you expect higher taxes later. For example, $7,000 a year for 30 years at 7%, with your rate rising from 22% today to 24% in retirement, leaves the Roth IRA ahead by about $13,700. This calculator compares the after-tax value of equal contributions to each. One caveat: a Roth IRA's annual limit is only $7,500 against the 401k's $24,500, and Roth IRA eligibility phases out at higher incomes, so most savers use both — the 401k for the match and scale, the Roth IRA for flexibility.
Formula & method
Roth IRA = C·F vs 401k = C·F·(1 − Tr) + savings
Both grow at the same rate; the Roth IRA is tax-free at withdrawal, the traditional 401k is taxed at your retirement rate.
Grow an equal contribution in each account over your time horizon.
Roth IRA: the full balance is tax-free at withdrawal.
Traditional 401k: subtract retirement tax, then add the invested up-front deduction.
Remember the 401k's employer match is extra money the IRA cannot match.
Guide
The amount you'd put into either account each year.
Your rate today and your expected rate in retirement.
Your expected return and years until withdrawal.
The tool shows both after-tax values; remember the 401k also earns the match.
Examples
Inputs
Result
Beyond the match, a Roth IRA's tax-free growth wins when your future tax rate is higher — plus it offers more investment choice.
Methodology
Compares equal contributions; in practice the 401k's employer match makes it the first priority regardless of tax treatment.
The Roth IRA has a lower annual limit ($7,500) than the 401k ($24,500) and income limits that phase out high earners.
Assumes the traditional 401k's up-front tax saving is invested; otherwise the Roth looks better than a fair comparison shows.
Ignores state tax, RMDs on the traditional 401k, and the Roth IRA's contribution-withdrawal flexibility.
Contribution limits, catch-up amounts, the early-withdrawal penalty and RMD rules follow the Internal Revenue Code as administered by the IRS, using the published figures for the 2026 tax year. Confirm current limits at IRS.gov, as they are adjusted annually for inflation.
Primary sources
Details
Priority order for most people: contribute to the 401k up to the full match, then a Roth IRA, then back to the 401k.
Roth IRA 2026 limit: $7,500 (plus $1,100 catch-up at 50+); 401k limit: $24,500.
Roth IRAs have income limits; a 401k (Roth or traditional) has none.
Roth IRA contributions (not earnings) can be withdrawn anytime tax- and penalty-free — far more flexible than a 401k.
A Roth IRA has no lifetime RMDs; a traditional 401k requires them from age 73.
How it connects
Applications
Decide where the next dollar goes once you've captured the full employer match.
Value the Roth IRA's penalty-free access to contributions and wider investment menu.
Balance pre-tax and tax-free buckets to control income in retirement.
Related tools
FAQs
For most savers the answer is "both, in order." Contribute to your 401k up to the full employer match first — that is an immediate, guaranteed return no IRA can offer. Beyond the match, a Roth IRA often wins on tax-free growth, wider investment choice, and flexibility (you can withdraw your own contributions anytime), especially if you expect higher taxes in retirement. Once the Roth IRA is maxed, return to the 401k for its much higher limit. For example, $7,000 a year in a Roth IRA for 30 years at 7%, with your rate rising from 22% to 24%, can leave you about $13,700 ahead of an equivalent taxable-later account. One caveat: the Roth IRA's $7,500 limit is far below the 401k's $24,500, and Roth IRA eligibility phases out at higher incomes.
Security & privacy
Uses the current IRS contribution limits, penalty rules and RMD tables — updated for 2026.
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Every calculation runs client-side in JavaScript. Nothing is sent to a server or stored.
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The match usually settles the first dollar — but the next ones are a real choice. Compare the after-tax outcomes to prioritise your savings.