The IRS is reminding self-employed people, gig workers, retirees and others who make estimated tax payments that their third quarter deadline was Sept. 15, 2023. You should make estimated payments if you expect to owe at least $1,000, after subtracting for withholding and credits, in 2023. Use the Tax Withholding Estimator at irs.gov to accurately calculate what you should pay. Accuracy is critical because even if you make estimated quarterly payments, the IRS could assess a penalty if you underpay for the year. When making last-minute payments, you’re strongly urged to file electronically. The fourth quarter estimated payment deadline will be Jan. 16, 2024.