How the Social Security payroll tax works now. The Social Security payroll tax rate is currently 6.2%, although it's not quite that simple. First of all, not all wages are subject to Social Security tax. As of 2016, only the first $118,500 is used to calculate Social Security tax -- anything above that amount is ignored. In other words, a worker who earns $118,500 per year pays the same Social Security tax as a worker who earns $1,000,000.