Get your taxes done using TurboTax

@brittmorrow13   - the payroll systems mimic the tax return.  So if you stated on the W-4 that you are filing MFS and have 2 children under the age of 17, the payroll systems are smart enough to realize you are eligible for tax credits (earned income and child tax credit).  The whole idea is to deliver those credits over the course of the year rather than getting a large refund in April.  

if you post your expected income for the year, I can explain the math, 

ps - why would you file MFS and not HOH?