I work on an as needed basis for a small hospital, the work is sporadic and my checks vary widely in amount. There is no federal income tax withheld from most of my checks because they tend to be less than $380. I file as married with no exemptions, allowances, or dependents. Corporate payroll says that federal income tax is not withheld from checks with gross pay of less than $380 but they are unable to make recommendations on how to increase how much federal income tax is withheld from my checks.