The first estimated payment is for Jan1 - March31 due Apr 15.
If your estimated tax plus withholding is not 25% of your Required Annual Payment ,
then you can be penalized, This is the simplified formula, default.
Bulking up the second payment to reach 50% can zero your penalty on the 2nd period.
Otherwise, use Form 2210 Schedule AI to further reduce or eliminate penalties,
@Bob4FrenchFries
Required Annual Payment is the smaller of 90% of the year's tax or
100% ( 110% for certain high income taxpayers) of the prior year's tax.
