You can avoid underpayment penalties for the current year if the amount withheld by employers plus estimated tax payments are an amount equal to last year's tax liability. If the Adjusted Gross Income is more than $150,000, then the estimated payments plus amount withheld has to be more than 110% of last year's liability. This is one exception that allows the taxpayers to avoid penalties and pay the balance of the tax is due on April 15th.