Not all subjects are created equal – but why?

Which Year 12 HSC Subjects Scale Best?

Choosing your HSC subjects? Here’s some information you should know about subject selection and scaling

Let’s start with one of the most frequently asked questions we receive at Talent, ‘What is scaling and why is it needed in the HSC?’

Scaling is the process of standardising marks so that they can be compared across subjects.

Without scaling, it would be impossible to compare a 91 in Mathematics Extension 2, with a 91 in Legal Studies. It’s almost like converting currency; how can we determine what other currencies are worth when compared to the Australian Dollar? First, we convert all their money into a single currency (AUD) that is universally accepted in Australia. In much the same way, the UAC converts all HSC marks into a single UAC score and aggregates the top 10 units, including 2 units of English.

The most important piece of advice you will receive in your HSC year is that not all subjects are created equal. The subjects with a high level of mathematical content tend to scale the highest, or to continue our analogy, harder subjects have the highest ‘exchange rate.’

In scaling marks, the UAC will adjust the highest mark, median mark and standard deviation so that all subjects are directly compatible – otherwise, how else can they be compared?

RELATED: Subject Selection Tips for Year 10 Students


As shown on the graph below, your ATAR is actually determined from the aggregate UAC score out of 500 (which includes 2 compulsory units of English and eight of your best units).

Examine the graph below carefully to determine what score out of 500 you need to get any ATAR. For instance, you can see quite clearly that if you were looking for an ATAR of 97, you would need an aggregate score of 420/500 or roughly 42/50 for each unit.

The ATAR is actually a rank not a mark. Once every student in the state has had their UAC score out of 500 calculated, the ATAR is determined on percentile ranks, rounded down to the nearest 0.05%. For instance, an ATAR of 99 means that you have performed better than 99% of the people in the state. The highest ATAR you can achieve is 99.95.

Which Year 12 HSC Subjects Scale Best?

How can I maximise my ATAR?

In order to maximise your ATAR, you should be acutely aware of how each of your subject scales and adjust your studies accordingly.

Most students intuitively know that easier subjects tend to scale downwards, while harder subjects like Mathematics Extension 1 & 2 tend to scale up.

These scaling graphs show you exactly what rank you need to score any ATAR. For more comprehensive information about subject scaling, check out our ATAR Calculator here.

The following table summarises the scaling of main subjects, and provides some simple decision rules to help you decide what to take:

Which Year 12 HSC Subjects Scale Best?

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