This is a follow up question to post I saw from 2023. My husband is a sole proprietor and pays quarterly estimated taxes. I am employed, receive a W2 and my taxes are taken out of my paychecks by my employer. When estimating his quarterly taxes, I didn't realize that the estimate is based on our total joint tax liability for the year prior. I read that we should for sure make sure 100% if not 110% of the our total tax is paid throughout the quarters. This includes his estimated payments AND the taxes that are taken out of my paycheck. (This is new to me, and likely the reason we received a decent refund last year, as he was overpaying). My question is, my employer takes out 1)federal income tax, 2)social security and 3)medicare. When calculating how much we owe for quarterly payments, I have to include what I have had taken out of my paychecks for that quarter, but do I include social security & medicare tax, or just the federal income tax? Thanks and I hope that makes sense.