In most cases, you must pay estimated taxes for any year if both of the following apply.
a) You expect to owe at least $1,000 in tax for the tax year, after subtracting your withholding and refundable credits.
b) You expect your withholding and refundable credits to be less than the smaller of: 90% of the tax to be shown on your current tax return, or 100% of the tax shown on your prior year tax returns;
Note. The above percentages may be different if you are a farmer, fisherman or higher income taxpayer.
a) New 4.6% tax for the high earners;
b) New 0.9% Medicare tax; and,
c) New 3.8% NIIT explained before
In addition, preparation of quarterly financial statements for business would be instrumental in calculating accurate estimated taxes.