its based off trial marks. trials marks wont be the same as hsc marks, but theyre similar
It's not necessarily Trial Marks, it can also be Raw Marks from anything - your final total at school, the average of papers you complete after Trials, etc.
For most, change in performance is usually seen in the period from after Trials until the HSC so people will most likely sit either paper at home after learning from their mistakes. It's important to keep in mind that Trials are also designed to be harder than the HSC so most will likely perform better in the HSC.
Since I accelerated Mathematics Advanced, when I reviewed the solutions after my exam (on the same day) I calculated my approximate Raw Mark, put it into the calculator that I linked earlier and was given an estimate of the aligned mark I would receive. To my luck, it was correct and it was the mark I received on Results Day.
All in all, ATAR calculators aren't the most reliable, especially since alignment changes from year to year and they are rarely updated to reflect this.
its such a huge waste of time