Two percentages, one required payment
The required annual payment is the smaller of those two safe harbors. Paying that amount on time, together with withholding, is how most people avoid an underpayment penalty, rather than by matching the final tax to the dollar.
If last year’s AGI was more than $150,000 ($75,000 if you will file married separately), last year’s tax is multiplied by 110% instead of 100%.
