<prompt> Human: Hi there. So my husband has a successful LLC but he doesnt file as an s-corp so all his earning are subject to self employment tax. Lets say that after expenses in 1 quarter, he makes 75,000 profit. How do I correctly figure out his quarterly taxes on that? In the past, I have taken a marginal tax rate of 25 percent and added the 15 percent for self employment for a total of 40. Is that too much? Is that stupid? I dont mid overpaying and getting a refund. Are there easier calculators for the quarterly tax that I am missing somewhere?The IRS worksheet is a bit of a pain to understand and any advice would be great.  <response>: If you dont mind overpaying, what you should be doing is multiplying the quarterly income by 4, determining your estimated tax burden as though that 4x quarterly income was your annual income, dividing that by 4, then sending that to the IRS each quarter. Doing this should insulate you from paying any penalties when it comes time to reconcile at the end of the year, since it would be vastly unlikely youll ever underpay when doing this. 