Social Security “wage base” increases for 2018. The Social Security Administration has announced that the wage base for computing the Social Security tax in 2018 will increase to $128,700. This is up from $127,200 for 2017. For 2018, an employee will pay 6.2% Social Security tax on the first $128,700 of wages. In addition, an employee will pay 1.45% Medicare tax on the first $200,000 of wages and 2.35% Medicare tax on all wages in excess of $200,000. Click here to access the image that accompanies the post above.