An employer-sponsored 401(k) retirement plan offers a wealth of benefits. First, most plans offer a variety of investment options. Second, all 401(k) contributions and earnings are tax-deferred. You pay taxes only when the money is withdrawn. Finally, many employers make matching contributions to your account. This calculator will help you figure out how much of your salary you might want to set aside, how fast that money is likely to grow at certain rates of return, and the benefits provided by employer contributions.