An employer-sponsored retirement savings account could be one of your best tools for creating a secure retirement. It provides two important advantages. First, all contributions and earnings are tax-deferred. You only pay taxes on contributions and earnings when the money is withdrawn. Second, many employers provide matching contributions to your account, which can range from 0% to 100% of your contributions. Use this calculator to see how increasing your contributions to a 401(k), 403(b) or 457 plan can affect your paycheck as well as your retirement savings. This calculator uses the 2017 withholding schedules, rules and rates (IRS Publication 15).