Penalty notice from PA Dept of Revenue after filing when Turbotax said taxes were done correctly

[mijohn]

I recently received a $20 penalty notice from the PA Dept. of Revenue for 2024's tax filing. I suspect this may be an underpayment penalty. I retired the prior year (2023) so I did not have any income in 2024 for which tax was withheld. (PA taxable income was less than $15k for 2024.) If this is in fact an underpayment penalty why did turbotax not pick up on this and alert me to the penalty when I filed so that I could pay the correct amount, including the penalty at that time?

[Bsch4477]

Underpayment penalty depends on several factors, one of which is the tax being paid on time quarterly. TurboTax has no way of knowing how the user wants to calculate the penalty.