we can't tell if you'll be subject to a penalty for the 3rd quarter. Not only do you owe income taxes on the consulting income but also self-employment tax. the Social Security amount will vary based on your Social Security Wages. The Medicare portion is 2.9% of .9235 of your net SE income
however, there are some safe harbors
There will be no federal penalties for not paying in enough taxes during the year if withholding and
a) timely estimated tax payments equal or exceed 90% of your 2023 tax or
b) timely estimated tax payments equal or exceed 100% of your 2022 tax (110% if your 2022 adjusted gross income was more than $150K) or
c) the balance due after subtracting taxes withheld from 90% of your 2023 tax is less than $1,000 or
d) your total taxes are less than $1,000
state laws differ
some other options
1) the default is that withholding is assumed to be 1/4 of the annual amount for each estimated tax period. You can use actual withholding for all periods.
2) if there are penalties you can also try using the annualized income method on page 3 of the 2210
try using the annualized installment method on page 3 of the 2210
state laws differ
