Using the 401k CalculatorEnter your own information into our 401k calculator. You can easily change the inputs to see what the impact will be. Areas highlighted in red will need to be filled in in order for the 401k calculator to produce meaningful results. Easily generate and view a full detailed report to see a year-by-year break down of your 401k account balance, cumulative contributions, employer match and investment returns. Also check out our many other 401k planning calculators including the 401k withholding calculator which shows how changing your 401k contributions affects your net take pay.