"There is no such thing as 100% profit. Percent profit by its very definition is "always" calculated based on the selling price. Pay $50 sell for $100 you made 50% profit. Pay $20 sell for $100 you made 80% profit. Pay $2 sell for $100 you made 98% profit. Now if you pay $50 and put the price at $100 you have "marked the price up" 100%, but when you sell it at $100 you made 50% profit. Don't believe me, go to any definition site on the internet and verify the definition of percent profit. It's the same all over U.S. no matter where you are and all over the world as well. It's better defined than caliber and gauge as there is no range of acceptable variances."
I agree that we are really splitting hairs. We all know that whether you want to call it return, margin, profit or whatever ...no one talks in terms of a percentage that can't exceed 100%. Can you imagine a couple gun dealers sitting around, bragging that "I made 89.345% profit on that deal!"? Of course not. They are much more likely to say "I tripled my money on that deal" or just "I made $400 on that deal." That's because the 'profit' method does not lend itself to the mental mathematics that people use in normal conversation.
If you're going to use profit as a percentage of selling price versus purchase price, you'd better be prepared to include in the same breath a statement of profits before and after taxes as well as the opportunity costs and the unburdened labor rate of the transaction. It'd be a shame to confuse the listener.
