How to read your target
Your ATAR is a rank, not a mark. To reach a target ATAR, what matters is your aggregate — the sum of your best 10 units of scaled marks, out of 500. This tool turns your target ATAR back into the aggregate and the average scaled mark you need, then shows the raw HSC marks that get you there.
The key idea is scaling. The same raw mark is worth different scaled marks in different subjects. A raw 85 in a high-scaling subject like Physics is worth more than a raw 85 in a lower-scaling one. That is why the table shows a lower raw mark for high-scaling subjects — they do more of the work for you. Even so, it is smarter to pick subjects you can do well in than to chase scaling, because marks matter more than subject choice.
Use this with the rest of the site. To check a real estimate from your marks, use the state calculators like NSW or VIC. To see how one subject scales, try the scaling calculator. Already have scaled scores? The ATAR predictor turns them into an ATAR. For the official method, see UAC.
For example, to reach a 95 ATAR you need an average scaled mark near 41 out of 50. That works out to about a raw 84 in high-scaling subjects, but closer to a raw 90 or more in lower-scaling ones. It is worth aiming a little above your target to give yourself a buffer.