TurboTax will calculate the estimated tax penalty and include it on Form 1040 line 38. Depending on when during the year you received your income (particularly if larger amounts were received late in the year) and any deductions or tax credits, you might find that annualizing your income will reduce the penalty. Annualizing requires you to identify the amounts of each that were received by the end of each of the tax quarters. (It can be an onerous task if you do not have detailed records readily available.)
