How a 401(k) calculator works
This calculator projects the future value of your 401(k) by combining your current balance, your regular contributions, any employer match, an assumed annual return, and the number of years until retirement. It compounds those contributions year over year to estimate your balance at retirement.
Employer matching is essentially free money: if your employer matches 50% of contributions up to 6% of salary, contributing at least 6% captures the full match. The calculator lets you model different contribution rates to see the long-term impact.
Why starting early matters
Compound growth rewards time more than amount. Because returns earn their own returns, a dollar invested in your 20s can be worth far more at retirement than a dollar invested in your 40s, even with smaller contributions.
Use the calculator to compare scenarios: raising your contribution by even one or two percent, or starting a few years earlier, often changes the final balance by tens of thousands of dollars.