NicolleR1
Expert Alumni

Get your taxes done using TurboTax

There are multiple reasons that could lead to not having "enough withholding" such as having multiple jobs, or having different source of income, such as self employment income or investment income. Another factor could be that both income combined put you in a higher tax bracket. 

It might also be an issue within the company you work for. You can check with your company's Payroll or HR department to see why are they not withholding enough.