# What will my Roth 401(k) be worth?

Projects a Roth 401(k) balance at retirement within the 2026 IRS contribution limits, and compares it after tax with a traditional 401(k) that costs the same take-home pay.

- Page: https://www.acalculator.org/finance/roth-401k-calculator
- JSON spec: https://www.acalculator.org/finance/roth-401k-calculator.json
- Version: 303c353d4e54

## Default answer

Example with the default inputs (Your age now 30, Age you retire 65, Salary $75,000.00, Yearly raise 3%, You put in 10%, Roth 401(k) balance now $0.00, Yearly return 7%, Tax rate now 22%, Tax rate in retirement 22%): Putting 10% of a $75,000.00 salary into a Roth 401(k) from age 30 grows to about $1,520,981.22 by 65.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| age | Your age now | Your age this year, in whole years. |
| retire | Age you retire | The age you stop contributing. Contributions run until the year before. |
| salary | Salary | Your yearly pay before tax this year. |
| raise | Yearly raise | How much your salary rises each year. |
| pct | You put in | Your Roth 401(k) contribution as a percent of your salary, up to the IRS limit. |
| balance | Roth 401(k) balance now | What is in your Roth 401(k) today. |
| rate | Yearly return | The yearly return on the account. It stays the same every year. |
| taxnow | Tax rate now | Your federal and state income tax rate on your last dollar of pay today. |
| taxlater | Tax rate in retirement | The income tax rate you expect on traditional 401(k) withdrawals in retirement. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| total | Your Roth 401(k) at retirement | The balance when you retire: today’s balance, your contributions and their growth. Tax-free when withdrawn as a qualified distribution. |
| contributions | Your contributions | Everything you put in from now until retirement. |
| growth | Investment growth | The balance at retirement minus today’s balance and your contributions. |
| yearContribution | You put in this year | Your Roth contribution this year, after the IRS limit. |
| limit | Your IRS limit this year | The most you can put in this year at your age: $24,500 plus any catch-up (2026 limits). |
| rothNew | Roth, new contributions only | What your contributions from now on grow to in the Roth 401(k), after tax (no tax on withdrawal). |
| tradAfter | Traditional, same take-home pay, after tax | The traditional 401(k) balance from the same take-home pay × (1 − tax rate in retirement). |
| tradBefore | Traditional balance before tax | The traditional 401(k) balance from the same take-home pay, before tax on withdrawal. |
| rothAhead | Roth comes out ahead by | Roth (new contributions only) minus traditional after tax. Shown when the Roth is ahead or even (under half a cent behind counts as even). |
| tradAhead | Traditional comes out ahead by | Traditional after tax minus Roth (new contributions only). Shown when the traditional is ahead. |
| payCap | Traditional capped at your pay | How many years the traditional contribution for the same take-home pay was cut to 100% of your salary (the annual additions rule). Shown only when it was. |

## Method

Each year: Roth = the lesser of (your % × salary) and your IRS limit (the base limit plus the catch-up for your age); balance = balance × (1 + R) + Roth ÷ 12 × s₁₂, with s₁₂ = R ÷ ((1 + R)^(1/12) − 1). Traditional with the same take-home pay = the lesser of Roth ÷ (1 − tax rate now) and the limit, grown the same way, then × (1 − tax rate in retirement).

## Assumptions

- The 2026 IRS limits stay the same in later years; employer contributions and the 415(c) total limit are not included.
- The return is the same every year. Fees are not included.
- Qualified Roth withdrawals are tax-free: you are 59½ or older and the account is at least 5 years old.
- The traditional comparison puts in more pre-tax money for the same take-home pay, and taxes all of it at the retirement rate.
- This is an estimate for planning, not financial advice.

## Worked examples

1. age = 55, retire = 56, salary = $300,000.00, pct = 20%, rate = 0%, taxnow = 24%, taxlater = 24% gives yearContribution = $32,500.00, limit = $32,500.00, total = $32,500.00. Source: IRS news release IR-2025-111: 2026 limit $24,500, catch-up $8,000 at 50 or older, $11,250 at 60 to 63 (https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500).
2. age = 61, retire = 62, salary = $200,000.00, pct = 25%, rate = 0%, taxnow = 24%, taxlater = 24% gives yearContribution = $35,750.00, limit = $35,750.00. Source: IRS news release IR-2025-111: 2026 limit $24,500, catch-up $8,000 at 50 or older, $11,250 at 60 to 63 (https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500).
3. age = 30, retire = 31, salary = $60,000.00, pct = 10%, rate = 0%, taxnow = 25%, taxlater = 25% gives total = $6,000.00, tradBefore = $8,000.00, tradAfter = $6,000.00, rothAhead = $0.00. Source: IRS news release IR-2025-111: 2026 limit $24,500, catch-up $8,000 at 50 or older, $11,250 at 60 to 63 (https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500).
4. age = 40, retire = 41, salary = $250,000.00, pct = 10%, rate = 0%, taxnow = 32%, taxlater = 32% gives total = $24,500.00, tradBefore = $24,500.00, tradAfter = $16,660.00, rothAhead = $7,840.00. Source: IRS news release IR-2025-111: 2026 limit $24,500, catch-up $8,000 at 50 or older, $11,250 at 60 to 63 (https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500).
5. age = 30, retire = 31, salary = $10,000.00, pct = 100%, rate = 0%, taxnow = 50%, taxlater = 50% gives total = $10,000.00, tradBefore = $10,000.00, tradAfter = $5,000.00, rothAhead = $5,000.00, payCap = 1 year. Source: IRS, Retirement topics: 401(k) and profit-sharing plan contribution limits: no more than 100% of compensation (https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-401k-and-profit-sharing-plan-contribution-limits).
6. age = 30, retire = 40, salary = $50,000.00, raise = 0%, pct = 12%, balance = $10,000.00, rate = 7%, taxnow = 22%, taxlater = 12% gives total = $105,197.38, contributions = $60,000.00. Source: IRS news release IR-2025-111: 2026 limit $24,500, catch-up $8,000 at 50 or older, $11,250 at 60 to 63 (https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500).

## FAQ

### What is a Roth 401(k)?

A 401(k) account where your contributions come out of your pay after income tax. In return, qualified withdrawals in retirement, growth included, are tax-free. A traditional 401(k) is the opposite: contributions are pre-tax, and withdrawals are taxed.

### How much can I put in a Roth 401(k) in 2026?

$24,500, shared with any traditional 401(k) contributions. If you are 50 or older by the end of the year you can add a catch-up of $8,000 ($32,500 in all), or $11,250 if you turn 60, 61, 62 or 63 in 2026 ($35,750).

### Is a Roth or a traditional 401(k) better?

For the same take-home pay, they come out even when your tax rate in retirement equals your tax rate now. A Roth wins if your tax rate will be higher in retirement, and a traditional wins if it will be lower. A Roth also wins when you put in the maximum, because $24,500 in a Roth is worth more after tax than $24,500 in a traditional account.

### What does “the same take-home pay” mean?

A pre-tax contribution lowers your tax, so it costs you less than its size. At a 25% tax rate, a $6,000 Roth contribution costs the same take-home pay as an $8,000 traditional one. The calculator compares those two, up to the IRS limit.

### When are Roth 401(k) withdrawals tax-free?

When they are qualified: you are 59½ or older (or disabled, or it is paid after your death) and it has been at least 5 years since your first Roth contribution to the plan. Other withdrawals can be taxed on the growth and face a 10% additional tax.

### Do high earners have to make catch-up contributions to a Roth?

Yes, from 2026. If your Social Security wages from the employer were more than $145,000 in the year before (adjusted for inflation), your catch-up contributions must go to a Roth account. This calculator already treats all contributions as Roth.

### Does this include my employer’s match?

No. Employer contributions and the total limit on employee plus employer money are left out. The 401(k) calculator includes a match.

## Sources

- Internal Revenue Service, IR-2025-111 (November 13, 2025): 401(k) limit increases to $24,500 for 2026. https://www.irs.gov/newsroom/401k-limit-increases-to-24500-for-2026-ira-limit-increases-to-7500
- Internal Revenue Service, Roth comparison chart (designated Roth 401(k), Roth IRA and pre-tax 401(k)). https://www.irs.gov/retirement-plans/roth-comparison-chart
- Internal Revenue Service, Retirement plans FAQs on designated Roth accounts (qualified distributions). https://www.irs.gov/retirement-plans/retirement-plans-faqs-on-designated-roth-accounts
- Federal Register, Catch-Up Contributions, final regulations (September 16, 2025). https://www.federalregister.gov/documents/2025/09/16/2025-17865/catch-up-contributions
- Internal Revenue Service, Retirement topics: 401(k) and profit-sharing plan contribution limits (no more than 100% of compensation). https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-401k-and-profit-sharing-plan-contribution-limits