I sold some company stock this year and need to know if I should file a quarterly tax return in this calendar year to avoid a penalty for underpayment?

[xmasbaby0]

You do not "file a quarterly tax return."    You only file one tax return for the year.    2024 tax returns can be filed in early 2025.   If you want to make an estimated payment, you can do that, but you are not going to prepare a tax return with that payment.

You can make a payment to the IRS online:

https://www.irs.gov/payments

[Mike9241]

There will be no federal penalties for not paying in enough taxes during the year if withholding and

1. timely estimated tax payments equal or exceed 90% of your 2024 tax or
2. timely estimated tax payments equal or exceed 100% of your 2023 tax (110% if your 2023 adjusted gross income was more than $150K) or
3. the balance due after subtracting taxes withheld from 90% of your 2024 tax is less than $1,000 or
4. your total taxes are less than $1,000

you can allocate 1/4 of your withholding to each tax period or use actual. estimated tax payments only count as of the date made. 

the period ends are 3/31,5/31,8/31 and 12/31

estimates are due by the 15th day of the month following the end of the period though if the due date falls on a weekend or holiday the payment is due the following business day

state laws differ

if you don't meet any of the exceptions above you can make an estimated tax payment but depending on when those gains were realized, you may still have a penalty though the amount would be reduced

[karenj900]

So if I sold the Stock in August but didn't pay the tax until November, I am already screwed?

[TomD8]

@karenj900 --

IRS Form 2210 will allow you to annualize your income, which may reduce or even eliminate any penalty.  See this TurboTax help article:

https://turbotax.intuit.com/tax-tips/irs-tax-forms/what-is-form-2210/L2z0haVWb

IRS Form 2210 (see Section AI):

https://www.irs.gov/pub/irs-pdf/f2210.pdf