Why did quickbooks take out so much social security?

Hello julie-sellin,

QuickBooks Online follows the Circular E guidelines in calculating Social Security which is 6.2% of the annual taxable income. In 2018, if an employee has reached the minimum taxable wage ($132,900), the Social Security contribution that'll reflect on the W-2 is $8,239.80. 

Let's try pulling up the Payroll Detail report of each employee. Then, manually calculate the SS deduction by multiplying the total taxable income to 6.2%. If it doesn't give you the correct contribution, try to review the paychecks to see if there's an incorrect calculation of SS deduction.

Please let us know if you have any questions. Thanks!