Nothing sir. There's no need for a trading app to calculate position sizing. The math is easy. The performance bond on a single NQ mini is ~17.5K. The position can drop 7000 points in a month. So that's a $140K hit to the account. That -NAV + the bond is -147.5K. At the roll, assuming you are at that bottom at roll date, you have to close your SINGLE mini NQ contract at a $140K loss. So for the next contract, you have -$140K to work with. So...How much money is adequate in the account? It ain't 10 grand, man!
I'll sing it to you instead. Easymon, c'mon. If yer looking for an app to calculate your position size risk for some quant or super-hi-freq thing on the fly right quick, then yeah, an app. But for the lay man, whatever? Just do the math in yer head!
7000 point NQ drop? What time frame would you put this in? Weeks months. Is this even possible, nah. The fed has got it covered to withstand any substantial collapse.
Instead of focusing on how to survive a 7,000 points drop in the NQ, I would suggest to break your head on a better trading system. In fact a trading system with a 7,000 points stop is not a trading system. If you trade such a system, there is something wrong with that system, with your knowledge about trading or with your available intelligence.
Account Size ____ Trade Risk % ____ Stop Loss in Ticks ____ Tick Value ____ Output = No. Contracts ____ Ideal would be a transparent Drag n Drop, above that overlays and stays on top showing 10 font Text only, Accepts Input beside each text line. Thin outline surrounds the word 'Output' and prompts the Calculate operation. No Menu Bar No Title Bar No Nuthin, lol. What languages might be among the easiest that can do this magic? "Trading an Engulfing Candle at Support & Resistance provides greater conviction." https://www.elitetrader.com/et/thre...t-right-here-baby.335635/page-10#post-5014575
If this suits you I could try and make a quick & dirty google spreadsheet template where you can just enter account size / % risk and instantly see multiple instruments without taking too much screen space. Other than that, I could also make it a web page to do exactly what you want. But ideally you want this as a plug-in in your broker. I'm planning on doing something like that for IB for myself.