Compare Roth and Traditional 401(k) After-Tax Retirement Value
Compare projected balances, employer match, current paycheck impact, future taxes and spendable retirement value. The model uses editable 2026 contribution limits rather than hiding assumptions.
Career and salary
Contributions and employer match
Current balances and investment assumptions
Tax and limit assumptions
Comparison method
Projection results
| Age | Salary | Roth-strategy employee | Traditional-strategy employee | Required Roth catch-up | Employer match R/T | Roth scenario | Traditional scenario |
|---|
What this Roth 401(k) calculator compares
Roth contributions generally reduce take-home pay now because they are made after tax, while qualified Roth withdrawals are generally tax-free. Traditional contributions may reduce current taxable income, but projected withdrawals are reduced by the retirement tax rate entered above. Employer match treatment is modelled separately.
Same gross contribution versus same take-home cost
Same gross contribution puts the same dollar contribution into each account. Same take-home cost increases the Traditional contribution by the current marginal tax benefit, subject to the annual limit, so the comparison does not ignore the immediate tax deduction.
Does the employee limit include employer match?
No. Employee elective deferrals use their own limit. Regular employee deferrals and employer contributions count toward the separate annual-additions limit, while eligible catch-up contributions are modelled outside that cap.
How is the high-earner Roth catch-up handled?
When enabled, the calculator places the catch-up portion of the Traditional strategy into Roth if prior-year wages from the sponsoring employer exceed the editable threshold. Plan availability, wages definitions and implementation can vary, so confirm with the plan administrator.
Does this calculate a 401(k)-to-Roth conversion?
No. Conversion-tax calculations are a different financial event and should not be mixed into a contribution-choice calculator.
Compare Roth and Traditional 401(k) choices on an after-tax basis
A Roth 401(k) and a Traditional 401(k) can hold the same investments, but the contribution tax treatment differs. Traditional employee deferrals generally reduce current taxable income and qualified withdrawals are generally taxable. Roth employee contributions are made after tax and qualified Roth distributions can be tax-free. The useful comparison is therefore not only the account balance—it is the projected spendable value after the modeled taxes.
Two contribution comparisons
Same gross contribution compares equal employee dollar contributions to each account. This is simple, but the Roth contribution usually reduces current take-home pay more because its tax is paid now. Same take-home cost estimates the larger Traditional contribution that could be made for the same current after-tax sacrifice. Both views are shown because choosing only one can favor a result by design.
Employer match treatment
The calculator separately models employee contributions and employer match. Employer matching rules vary by plan, including the match rate, compensation percentage ceiling, vesting and whether a plan permits Roth treatment for employer contributions. The employer-match destination is therefore an explicit input rather than a hidden assumption.
2026 limit defaults
The shipped 2026 planning defaults use a $24,500 employee elective-deferral limit, an $8,000 age-50 catch-up amount, an $11,250 higher catch-up amount for eligible ages 60 through 63, and a $72,000 overall defined-contribution limit. These values are editable because tax law, plan documents and individual eligibility can differ. They should be reviewed when the calendar year changes.
Investment assumptions that materially affect the result
- Years until retirement and current account balances.
- Salary growth and contribution frequency.
- Investment return before fees and the annual fee rate.
- Current federal and state marginal tax assumptions.
- Expected marginal tax rate applied to Traditional withdrawals.
- Employer match and plan contribution limits.
Understanding the break-even tax rate
The break-even result estimates the retirement tax rate at which the modeled spendable values are equal. A future tax rate above that point tends to favor the Roth scenario under the selected assumptions; a lower rate tends to favor the Traditional scenario. It is not a prediction of future law and does not capture every deduction, credit, required distribution, Social Security interaction or estate-planning issue.
Why the year-by-year table matters
The projection table shows salary, employee contribution, employer match and ending balances by year. This exposes contribution-limit caps and makes it easier to identify unrealistic salary, return or match assumptions. Competitor calculators that show only one final number can hide those mechanics.
Can I split contributions between Roth and Traditional?
The comparison models separate all-Roth and all-Traditional employee scenarios to show the difference clearly. A real plan may permit a split, subject to one combined employee deferral limit. Users can run several contribution amounts to evaluate a preferred mix.
Is the higher projected account balance always the better result?
No. Compare the spendable after-tax result, current take-home effect, liquidity needs, tax diversification and plan rules—not the headline balance alone.
Is this tax or investment advice?
No. It is an educational projection based on user-entered assumptions. Plan documents and qualified tax or financial professionals should guide an actual election.
Roth 401(k) vs Traditional 401(k) Calculator: formula-based step-by-step solution
This Roth 401(k) vs Traditional 401(k) Calculator worked derivation uses the published default state. Its live formula panel replaces these values whenever an input, unit, mode, date, material, or scenario changes.
Annual contribution = employee contribution + employer matchFuture value of recurring contributions = payment × ((1 + r)^n - 1) ÷ rTraditional after-tax value = traditional future value × (1 - retirement tax rate)Roth after-tax value = Roth future value because qualified withdrawals are modeled tax-free
1. Governing formulas and numeric substitution
- Formula 1:
Annual contribution = employee contribution + employer matchDefault-value substitution:Annual contribution = (10) + employer match - Formula 2:
Future value of recurring contributions = payment × ((1 + r)^n - 1) ÷ rDefault-value substitution:Future value of recurring contributions = payment × ((1 + (50))^n - 1) ÷ (50) - Formula 3:
Traditional after-tax value = traditional future value × (1 - retirement tax rate)Default-value substitution:Traditional after-tax value = traditional future (10) × (1 - (20) (50)) - Formula 4:
Roth after-tax value = Roth future value because qualified withdrawals are modeled tax-freeDefault-value substitution:Roth after-tax value = Roth future (10) because qualified withdrawals are modeled (20)-free
2. Variables and measurement units used
- Current age =
35 - Retirement age =
65 - Annual salary ($) =
90000$ - Prior-year wages from this plan sponsor ($) Used only for the optional high-earner Roth catch-up rule. =
90000 - Annual salary growth (%) =
3% - Employee contribution method =
percent - Employee contribution =
10 - Employer match rate (%) =
50% - Match applies up to salary (%) =
6% - Employer match tax treatment =
traditional - Contribution timing =
12 - Current Traditional 401(k) balance ($) =
50000$ - Current Roth 401(k) balance ($) =
20000$ - Expected annual return (%) =
7% - Annual plan/investment fees (%) =
0.5% - Current federal marginal rate (%) =
22% - Current state/local marginal rate (%) =
5% - Expected retirement withdrawal tax rate (%) =
20% - Employee deferral limit ($) =
24500$ - Age 50+ catch-up ($) =
8000$ - Age 60–63 higher catch-up ($) =
11250$ - Total plan contribution limit ($) Catch-up contributions are treated outside this annual-additions cap. =
72000 - Apply high-earner Roth catch-up treatment? =
yes - Roth catch-up wage threshold ($) =
150000$ - Annual limit growth (%) =
0% - How should the two scenarios be compared? =
sameGross
3. Roth 401(k) vs Traditional 401(k) Calculator final evaluation: this calculator’s production engine evaluates the substituted relationship with unrounded internal precision; its subject-specific result cards, table, and visual report the rounded final answer and verification quantities.
Formula-based calculator guide
Roth 401(k) Vs Traditional 401(k) Calculator: formula, steps, units and verification
roth 401(k) vs traditional 401(k) calculator is designed for a transparent calculation rather than a black-box answer. Roth 401(k) Vs Traditional 401(k) Calculator: compare Roth and Traditional 401(k) balances, match, current paycheck effect, retirement taxes and after-tax.
How to use the roth 401(k) vs traditional 401(k) calculator in 5 steps
- Choose the required mode. Select the calculation path that matches the quantity you know and the result you need.
- Enter source values. Use measured, documented or assignment values rather than rounded estimates whenever possible.
- Confirm every unit. The roth 401(k) vs traditional 401(k) calculator converts supported units before formula substitution, so each selector must describe the entered number.
- Run the calculation. Review the displayed formula, normalized values and numeric substitution before accepting the final result.
- Verify the answer. Reproduce the substitution manually and check whether the output is reasonable for the stated assumptions.
Roth 401(k) Vs Traditional 401(k) Calculator formula and unit checks
The roth 401(k) vs traditional 401(k) calculator keeps source inputs, canonical calculation units and displayed output units separate. This prevents a correct formula from producing a wrong answer because feet were treated as meters, percentages as decimals, or time values as the wrong interval.
For an independent check, copy the formula shown by the calculator, substitute the unrounded canonical values, preserve full precision through intermediate operations and round only the final result. The verified answer should match both the displayed number and its measurement unit.
How to interpret the roth 401(k) vs traditional 401(k) calculator result
A result is useful only when its assumptions match the real problem. Compare the answer with expected ranges, inspect any warning or boundary message, and test a nearby input to confirm that the output changes in the direction predicted by the governing relationship.
The roth 401(k) vs traditional 401(k) calculator provides an educational and planning result. For regulated, medical, structural, financial, laboratory or safety-critical decisions, verify the inputs and method against the applicable professional requirements before acting.
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Roth 401(k) Vs Traditional 401(k) Calculator quick verification checklist
Before saving or reporting a result from the roth 401(k) vs traditional 401(k) calculator, confirm the input source, unit selections, formula mode, intermediate substitution, final unit and rounding rule. These checks make the calculation reproducible and easier to audit.
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