Once you have entered all of the information needed to determine your MAGI for the purpose of a Roth IRA contribution, TurboTax will indeed inform you of an excess Roth IRA contribution made for the current tax year when you step through the Roth IRA contribution section. See on TurboTax's Roth IRA Contribution Limit Worksheet. the calculation of the permissible Roth IRA contribution.
