For 2018, the Social Security Administration (SSA) announced that the Social Security taxable wage base will be $128, 400. This is the maximum amount of earnings subject to Social Security tax for 2018.
Initially, the SSA announced that the wage base would increase by $1,500 — from $127,200 to $128,700 maximum taxable earnings. However, the agency later revised that maximum to $128,400, an increase of $1,200 from last year.
According to the SSA, this lower taxable maximum amount is due to corrected Forms W-2 that a national payroll service provider provided to Social Security in late October 2017.
The taxable maximum amount change took effect January 1, 2018.