Flechette

@Bullfighter Thank you for your reply. I think you are right; a lot of these tools make assumptions and those assumptions can wildly affect the results. I had not given as much thought to how IV affects outputs and assumed that they didn't have as wide as an effect as they evidently do. I will try to factor that in to my investments, although I do not know quite how since the actual IV in the future changes. Complicated!

@TrustyJules Thank you so much for your explanation! First off, I am sorry that I forgot to post the strike prices ! 😳 Yes, you assumed them correctly. I did take the midpoints as you suggested when I posted the results earlier. I note that OptionsProfitCalculator and Options Strat are virtually identical, so I am assuming that they use very similar algorithms. Your explanation in the first paragraph makes sense even though at first I got nowhere near the $278 max that your model did. It defaults to buying at market prices but you can input whatever you want to be more accurate for your trade, which I did. I chose the midpoints. It got very close to your number: $270.95. So I think these two tools are probably pretty accurate (as can be) given the right inputs (the actual price paid for the two legs and not market, as well as the correct IV assumption...which is essentially an educated guess). While playing around with Options Strat there is a IV bar you can slide. I see how much IV affects the results. A lot. ETrade is another story. They have two tools (the basic one and the "Power ETrade" one) that give wildly different results. This is alarming. Power ETrade and it has a slider for submitting different positions at a certain price. It takes the cumulative of the position so you do not get to specify one of the legs exactly. It could be that one of the legs was higher than the midpoint and the other lower...but it results in the same value. I buy at the midpoint most often. The basic ETrade tool allows you to choose "debit", "even" or "credit". I am assuming that this means "bid mid ask". I suspect if I play with the IV and make sure that the buy/sell prices are accurate then these tools will be more accurate too. Maybe. But one thing I learned is that there are a LOT of assumptions in these tools and things like IV can be guessed at but not definitively known in the future. By the way, how do they calculate IV? Is it a six month in arrear running average or something? Right now I just have to accept the numbers given. I can't really ascertain what a recent large drop or large gain has done to it. Thank you so much for your very detailed explanation!

Hello, I am new here because Reddit never lets me post a question. Here is my general question: Why do different Options Profit Calculators yield such different results? The differences are so large I cannot trust them. I used to just use Power Etrade, but recently I started comparing the results to other options calculators with huge differences. I am trying to do a relatively simple PMCC on WMT and the Etrade options calculator, Power Etrade Calculator, OptionsProfitCalculator.c om and OptionsStrat all give different predictions. What is going on? Input: Long call: 16 Jan 26: $37.30 Short call: 24 May 24: $0.56 Results: Max profit Etrade: $31.95 MaxProfit Power Etrade: $105.3 OptionsProfitCalculator: $136 Options Strat: $136.70 What is going on? Thanks for any help.