Retirement Planner: 401(k) + Roth IRA + Taxable
Most savers hold more than one account. Project a traditional 401(k)/IRA, a Roth, and a taxable brokerage account together — same return, same horizon — and see each ending balance, the combined total, and the 4% rule first-year figure. How the three account types are taxed is covered in the companion guide, 401(k), Roth IRA, and Taxable Accounts: How They Fit Together.
Your multi-account projection
Example: age 35 → 65 at 6% — $50,000 + $500/mo traditional, $20,000 + $250/mo Roth, $10,000 + $250/mo taxable → about $1,486,321 combined (pre-tax).
Three accounts, one growth engine
Compounding does not care which account a dollar sits in, so each bucket runs through the same arithmetic: monthly compounding at the annual return divided by twelve, with contributions added at the end of each month until your retirement age. The worked example — age 35 retiring at 65 at an assumed 6% return — is computed at build time by the same tested engine as the calculator above:
| Account | Start | Monthly | You contribute | Growth | Ending balance |
|---|---|---|---|---|---|
| Traditional 401(k)/IRA (pre-tax) | $50,000 | $500 | $230,000.00 | $573,386.28 | $803,386.28 |
| Roth | $20,000 | $250 | $110,000.00 | $261,580.26 | $371,580.26 |
| Taxable brokerage | $10,000 | $250 | $100,000.00 | $211,354.51 | $311,354.51 |
| Combined (pre-tax) | $1,486,321.06 | ||||
The 4% rule converts that combined balance into a first-year income figure: $59,452.84 in the example. It is a heuristic from William Bengen's 1994 study — withdraw 4% of the starting portfolio in year one, adjust for inflation after — not a guarantee; The 4% Rule guide covers where it comes from and where it strains.
The combined number is pre-tax — and the after-tax view is an illustration
The three ending balances are not the same kind of dollars. Traditional 401(k)/IRA withdrawals are generally taxed as ordinary income, qualified Roth withdrawals are not, and the taxable account pays tax along the way. The combined figure is therefore a pre-tax planning number. If you enter an assumed tax rate, the calculator shows an illustration: the traditional balance discounted by your own assumed rate, with the Roth and taxable balances re-added unchanged. The tax rates and brackets that will exist at your retirement are unknowable, and this site does not guess them — the rate in that field is your assumption, applied mechanically. The illustration also does not model the tax the taxable account owes on its own dividends and gains, so its slice of the after-tax figure is still overstated. The mechanics of all three account types — contribution, growth, and withdrawal taxation — are laid out in the companion guide, 401(k), Roth IRA, and Taxable Accounts: How They Fit Together.
What this tool does not model
The employer match formula. Enter match dollars directly in the traditional monthly contribution — the 401(k) Calculator converts a match formula and salary into that dollar figure. Contribution limits. The IRS adjusts the 401(k) and IRA limits annually; this page quotes no figures — irs.gov publishes the current ones. The Roth IRA Calculator models the Roth leg on its own, and the Investment Calculator handles any single account without retirement framing. Taxes on the taxable account's gains as they accrue. Social Security and pensions. Return variability. Real returns arrive in an unpredictable order, not as a smooth average, and a run of poor returns near retirement does disproportionate damage — sequence-of-returns risk. A projection built on a constant return shows the shape of the compounding, not the range of outcomes.
Frequently asked questions
Why is the combined balance labeled pre-tax?
Because the three buckets hold different kinds of dollars. Every traditional 401(k)/IRA dollar withdrawn is generally taxed as ordinary income, a qualified Roth dollar is not, and a taxable brokerage account pays tax along the way on dividends and realized gains. Adding the three ending balances is valid growth arithmetic — compounding does not care which account a dollar sits in — but the sum is a planning figure, not spendable money.
What does the assumed tax rate field actually do?
It is an illustration control, nothing more. When a rate is entered, the calculator multiplies the traditional ending balance by (1 − rate) and re-adds the Roth and taxable balances unchanged. The calculator does not suggest a rate, because the tax rates and brackets that will apply decades from now are unknowable and this site does not guess them. The illustration also does not model the tax the taxable account pays on its own gains.
Where does the employer match go?
Into the traditional monthly contribution field, as dollars. This tool models each account as a balance plus a level monthly contribution, so a match formula like "50% up to 6% of pay" has to be converted to its dollar amount first — the 401(k) Calculator on this site does that arithmetic from your salary and match terms.
Does this calculator enforce contribution limits?
No. The IRS adjusts the 401(k) and IRA limits annually, which is why this page quotes no dollar figures — the current limits are published at irs.gov, and that statement is current as of September 2026. A taxable brokerage account has no contribution limit, which is the structural reason it appears alongside the tax-advantaged accounts in many multi-account plans.
What does this calculator leave out?
Taxes on the taxable account’s dividends and gains along the way, the employer match formula (enter match dollars in the contribution field), contribution limits, Social Security, pensions, required minimum distributions, and the fact that real returns arrive in an unpredictable order rather than as the smooth average modeled here — a hazard known as sequence-of-returns risk. It projects growth mechanics; it does not predict outcomes.
Not financial advice: a general educational estimate that assumes a constant rate of return and excludes taxes on the taxable account's gains, contribution limits, Social Security, and market volatility. The after-tax view is an illustration built on your own assumed rate. Your real results will differ. Values are processed locally in your browser and never transmitted. See the methodology page.