There is no estimated tax penalty if you do one of the following [1] :Pay 90% of your total taxPay 100% of your previous yearu2019s liability*Underpay less than $1000The second one is the key, as it requires no guesswork. Simply take your previous yearu2019s tax liability (2023 Form 1040, line 63), divide by 4, and make sure youu2019ve paid that much each quarter, in combined withholding and estimated tax payments.If you end underpaying, you will have to settle it up at the end of the year, but there will be no penalties. You can, of course, send in more if you like getting big refunds of your own money.The only time you wouldnu2019t want to use this is if you are making much less this year than last year, and you would rather send in less. In that case, you can either fill out a mock return and calculate the amount, or you can just wing it by multiplying your tax rate by your income. (Remember the 15% for social security tax!). In your case, that would come to an even $1000 per quarter (in addition to withholding on any wages). This will be too much since we havenu2019t accounted for deductions and exemptions.Consult a qualified tax professional for reliable advice.* 110% if your AGI is over $150,000 (married) or $75,000 (single)Footnotes[1] https://www.irs.gov/pub/irs-pdf/...