This 401(k) savings calculator allows users to model 401(k) contributions and returns over time. It calculates that with a starting balance of $0, 10% annual contributions from age 35-64 at a 6% average annual return, the estimated 401(k) balance after 30 years would be $675,139, including $263,693 in total contributions. The summary also provides projected ending salary, annual salary increases, employer matching rates, and investment return assumptions.