I certainly wouldn't suggest that you turn around and sell a wine bottle for your purchase cost; there absolutely are costs that you have, both for food and wine. Since those are the things you're selling, you need to add a markup to cover all your costs, just like any other business. But I still don't understand why most wine markups are based on multiplication. Granted, cheaper bottles tend to get marked up more and more expensive bottles tend to get marked up less, so it's (usually) not an exact multiplication. Many of the items you list seem like they're only somewhat variable (the new vacuum cleaner obviously being an unforeseen expense), though I suppose one could point out that income is highly variable. It's something that's always confused me; if the costs are static within a certain range, why not just markup wine and food to handle those costs. You didn't pay more in rent with (what I see in retail as) a $50 bottle of wine then you did with a $25 bottle, but I might be paying $100 for the first bottle, and $50 for the second (not knowing your markup strategy, of course). In fact, none of the items you list seem like they'd cost you more with a more expensive wine. Just curious; I know restauranting is a tough, tough business. And I'm all for restaurants I like staying in business. But I've never heard a good reason for why wine markups are based on multiplication, other than "we use wine sales to compensate for low food profits".