This was the first time I had to pay estimated taxes, on my 2020 tax return, I followed the payment schedule generated by TurboTax at the end which were the estimated tax vouchers. I paid all of the amounts before the due date each quarter, but I was hit with a ~$150 penalty when I recently filed for 2021. My AGI for 2021 was not >$150K, so paying 100% of the previous year's taxes should've prevented any penalties, I am trying to figure out if I did something wrong or is on TT's end. Also, what amount is being defined as "100% of previous year's taxes" is it "Total Tax" or "Payment Due (which is after any payments/credits)? If it's the former, it seems like TurboTax did it incorrectly and divided my payment due by four for my vouchers, which means I didn't pay enough.
