About the 401(k) Calculator
A 401(k) is a US workplace retirement plan where you put in a share of your pay and many employers add a match. Because contributions grow for decades, small changes today make big differences later. This calculator projects your balance at retirement from your age, your planned retirement age, your current balance, your salary, how much of it you contribute, the employer's matching rule, how fast your pay rises and the yearly return you expect. It shows how much came from you, from your employer and from investment growth, and what the final balance might be worth in today's money after inflation. It also works as a model for similar plans in other countries.
Updated October 2026
How to use the 401(k) Calculator
- 1Enter your age, retirement age, current balance and yearly salary.
- 2Enter the percentage of salary you contribute.
- 3Enter your employer's match: the share of your contribution they add, and the salary cap on matching.
- 4Enter the expected salary growth, return and inflation.
- 5Read the projected balance, the split between contributions and growth, and today's-money value.
Worked example
A 30-year-old earning 70,000 with 25,000 already saved contributes 8 percent and gets a 50 percent match up to 6 percent. Pay rises 3 percent a year and the portfolio returns 6 percent. By 65, the balance is about 1,476,700. Of that, 338,600 came from the employee, 127,000 from the employer and roughly 986,200 from growth. With 2.5 percent inflation that is worth about 622,200 in today's money.
What makes the biggest difference
- Starting early: each extra year of growth compounds on everything before it.
- Capturing the full match.
- Raising your contribution when your pay rises.
- Keeping fees low.
- Not cashing out when you change jobs.
Using the result sensibly
Treat the projection as one possible path, not a forecast. Try lower returns and higher inflation to see a cautious case, and check what the balance might provide in yearly income by using a withdrawal rate of around 3.5 to 4 percent. Revisit the numbers each year, because pay, markets and your plans change.
Related tools
The Retirement Calculator looks at how much you need overall, the Roth IRA Calculator models another popular account, the Compound Interest Calculator shows growth with different compounding and the Inflation Calculator explains the cost-of-living effect.
Features
- Employer match with a cap
- Salary growth built in
- Contributions, match and growth shown separately
- Value in today's money
- Monthly compounding
- Works for any currency
Frequently asked questions
How does an employer match work?
Typically, the employer adds a percentage of what you contribute, up to a limit. A common deal is 50 percent of your contributions up to 6 percent of your salary. If you contribute 8 percent, the match is calculated only on the first 6, so you receive 3 percent of salary from your employer.
What return should I assume?
Long-run averages for a stock-heavy portfolio have been in the range of 6 to 8 percent a year before inflation, but individual decades differ widely and there are no guarantees. Many planners use 5 to 6 percent to be cautious.
Why show today's money?
A balance of 1.4 million in 35 years will buy less than 1.4 million does now. Dividing by the inflation factor expresses the result in terms of today's prices, which gives a better feel for what it means for your standard of living.
How much should I contribute?
Many advisers suggest saving 10 to 15 percent of pay, including the employer match, over a career. At the very least, contribute enough to get the full match, since it is an immediate return on your money.
Does it include taxes?
No. Traditional 401(k) withdrawals are usually taxed as income, while Roth accounts are taxed on the way in. Fees and fund costs are not included either, but you can lower the return to reflect them.
Is there a contribution limit?
Yes. The tax authority sets a yearly cap on employee contributions that is adjusted most years, with extra catch-up room for people over 50. Check the current figure, as the calculator does not enforce it.