Here's the rule for underpayment penalties:::
there's no penalty if you owe less than $1,000 in tax after subtracting withholding and refundable credits, or if you paid withholding and estimated tax of 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.....https://www.irs.gov/taxtopics/tc306
