How come the highest ATAR I can get is only 99.75? I put 50 for all my subs. Is atarcalc not that accurate or is it because I only have 5 subjects? did I need to have taken spesh or latin or something, does anyone know lol
First of all, it's definitely not the fault of the calculator--it's as accurate as can be. That being said, 2014 was a particularly competitive year to get a high ATAR in, as a very strong aggregate was required in comparison to other years. In this case, where you would've got 99.75, if you got an identical aggregate in the year before it would've sat at a 99.85. This changes from year to year, and is something you can't control.
To answer the other part of your question: yes, it's fundamentally due to your subject choices. With only 5 subjects, you miss out on a possible +10% boost from a sixth subjects. Similarly, because you have no subjects that scale above 50, it would be theoretically impossible for you to get a 99.95 (in 2014) even with a sixth subject (assuming said subject doesn't scale above 50). Don't let this get you down though, as these are marginally small gaps. You can still do extremely well with only 5 subjects, and scaling takes care of itself at the end of the day that you shouldn't feel disadvantaged for not doing something like Spesh or Latin. If it makes you feel any better, even if I 50 all of my subjects this year (including a LOTE and Methods), I would still only achieve a 99.90--it's just so competitive at the top of the bell curve. Hope this clarified it for you a bit.