in theory, of the amount that is supposed to be paid to avoid penalties, 25% was due 5/17, 25% 6/15, 25% 9/15 25% 1/15/2022. however, when it comes time to actually file your return you can use the annualized income method to see if that method reduces or eliminates penalties.
here are the actual rules
There will be no federal penalties for not paying in enough taxes during the year if withholding
1) And timely estimated tax payments equal or exceed 90% of your 2021 tax
or
2) And timely estimated tax payments equal or exceed 100% of your 2020 tax (110% if your 2020 adjusted gross income was more than $150K)
or
3) the balance due after subtracting taxes withheld from 90% of your 2021 tax is less than $1,000
or
4) your total taxes are less than $1,000
state laws differ
