Received a letter from IRS for dollars owed due to tax penaltiy computation error. I found where the error was on Turbo Tax, but was not an area I manually entered.

[liv1079]

How do I find where this amount came from in Turbo tax?

[VolvoGirl]

Was it for an underpayment penalty on 1040 line 38?  Did your return have a penalty listed?  It is just an estimated amount.  It's common for the IRS to send you a bill for more or even a refund if you have an amount on line 38.  It's from form 2210.  

If you do not pay enough tax through withholding, you may have to pay a penalty for underpayment of estimated tax. Even if you are getting a refund you can still owe a penalty for not paying in evenly during the year.  Generally, most taxpayers will avoid this penalty if they owe less than $1,000 in tax after subtracting their withholdings and credits, or if they paid at least 90% of the tax for the current year, or 100% of the tax shown on the return for the prior year, whichever is smaller. It is included in your tax due or reduces your refund.