401(k) Calculator
Project 401(k) growth with employer match.
Details
of salary
401(k) balance at retirement
$599,615
In 30 years, at age 65
Your contributions
$151,000
Employer match
$0
Investment growth
$448,615
Effective match
0% of pay
This projects what your 401(k) could be worth at retirement. Enter your age, salary, current balance, what you contribute and your employer's match.
It returns the projected balance and splits it into your own contributions, the employer match and investment growth, so you can see where the money actually came from.
What a 401(k) is
A 401(k) is a retirement account offered through your employer. Money goes in from your pay before tax, grows without being taxed each year, and is taxed when you withdraw it in retirement.
The tax break matters, but the employer match matters more. Many employers add money when you contribute, commonly 50 cents or a dollar for each dollar you put in, up to a percentage of your salary.
That match is an immediate return on your money before any investment growth. A 50% match is a guaranteed 50% gain the moment it lands, which nothing else in personal finance reliably offers.
The contributions are a small fraction of the final figure. Everything else is time doing the work, which is why the years you start matter more than the amounts.
What to enter
- Current age and retirement age
- The gap between them is the number that matters most. Ten extra years of growth typically outweighs any realistic increase in contributions.
- Current 401(k) balance
- What you already have. Zero is fine.
- Your contribution
- As a percentage of salary. At minimum, contribute enough to collect the full employer match.
- Employer match and match limit
- Most plans express this as 'X% of what you contribute, up to Y% of salary'. A 50% match up to 6% means putting in 6% earns you another 3%.
- Expected annual return
- A long-run assumption. 6 to 7% is a common estimate for a diversified portfolio, but real returns vary hugely year to year.
How 401(k)s differ from other retirement accounts
- Traditional 401(k)
- Contributions reduce your taxable income now; withdrawals are taxed in retirement. Best if you expect a lower tax rate later.
- Roth 401(k)
- Contributions are taxed now, withdrawals are tax-free. Better if you expect to be in a higher bracket later, which often suits younger savers.
- IRA
- Opened by you rather than an employer, with lower contribution limits and no match, but a far wider choice of investments. See the IRA calculator.
- Vesting
- Your own contributions are always yours. Employer match may take several years to become fully yours, which matters if you change jobs.
What this assumes
The return is steady every year. Real markets are not, and the sequence of returns near retirement matters a great deal.
Salary and contribution stay constant unless you change them. Most people's contributions rise with pay over a career.
Contribution limits are set annually by the IRS and are not applied here, so check the current year's cap.
Figures are in future dollars, so inflation will reduce their buying power.
How to calculate your 401(k) at retirement
Each year, add what you and your employer put in, then grow the whole balance.
- your contribution
- Salary × your percentage
- match
- Whatever the employer adds, up to their limit
Work out your contribution. Salary times your percentage. On $50,000 at 6%, that is $3,000 a year.
Add the employer match. A 50% match up to 6% adds $1,500, so $4,500 goes in altogether.
Grow the whole balance. Apply the annual return to everything, including previous years' growth.
Repeat to retirement. The final decade produces the largest gains, because it compounds on the biggest balance.
See a worked example: starting at 30 on $50,000, contributing 6% with a 50% match
- Salary
- $50,000
- You contribute
- 6%, or $3,000 a year
- Employer match
- 50% up to 6%, so $1,500
- Return
- 7% a year to age 65
$4,500 goes in each year across 35 years.
Your own share of that is $105,000 and the employer's is $52,500.
With 7% annual growth the balance reaches about $665,600.
So roughly $158,000 was paid in and the rest is growth. Time did far more work than the deposits.
About $665,600 at 65
Frequently asked questions
- How much should I contribute to my 401(k)?
At an absolute minimum, enough to collect the full employer match. Contributing less leaves guaranteed money behind.
Beyond that, a common target is 15% of income towards retirement including the match. Whether that is achievable depends on your other commitments, but the match portion is not really optional.
- What does 'employer match 50% up to 6%' mean?
Your employer adds 50 cents for every dollar you contribute, until your own contribution reaches 6% of salary.
On $50,000: contribute 6% ($3,000) and they add $1,500. Contribute 3% and they add only $750, so you lose half the available match. Contribute 10% and they still add just $1,500, because the match caps at 6%.
- Traditional or Roth 401(k)?
Traditional cuts your tax bill now and taxes withdrawals later. Roth does the opposite: taxed now, tax-free later.
The deciding question is whether your tax rate will be higher now or in retirement. Early-career savers on lower incomes often favour Roth; higher earners near their peak often favour traditional. Splitting between both hedges the guess.
- What happens to my 401(k) if I change jobs?
Your own contributions are always yours. The employer match may be subject to vesting, so leaving early can forfeit some of it.
You can usually leave it, roll it into the new employer's plan, or roll it into an IRA. Cashing it out is the expensive option: income tax plus, generally, a 10% penalty before 59½.
- What return should I assume?
Six to seven percent is a common long-run assumption for a diversified portfolio, and it is deliberately conservative.
It is an average across decades, not a yearly expectation. Some years are strongly negative, and the sequence matters most in the years just before and after you retire.
Problems people actually run into
Contributing less than the match
This is the most expensive common mistake in the whole of personal finance, and it is entirely avoidable. Contributing 3% where the match runs to 6% leaves half the free money behind, every year, permanently.
On a $50,000 salary that is $750 a year forfeited. Over a career, with growth, it is easily six figures. Check your plan's match terms today rather than at your next review.
Cashing out when changing jobs
A balance of a few thousand can feel too small to bother rolling over, so people take the cash. That triggers income tax and generally a 10% early withdrawal penalty.
Worse is what it costs in growth. A $10,000 balance left alone for 30 years at 7% becomes about $76,000. Cashing it out swaps that for perhaps $6,500 after tax and penalty.
Results are estimates for general information only and are not professional financial, medical, or legal advice. Read our full disclaimer.
Sources
- Retirement topics: 401(k) and profit-sharing plan contribution limits · Internal Revenue Service
Last updated: September 13, 2026
