Generally, you avoid an underpayment penalty if the total tax owed is than $1,000 after subtracting your withholdings and credits, or if you paid in at least 90% of the tax for the current year, or 100% of the tax owed for the previous year, whichever is smaller.
Please see the attached for more information:
https://www.irs.gov/businesses/small-businesses-self-employed/estimated-taxes
