A Guide to High-Scaling HSC Subjects


You’ve probably heard people in the past talking a lot about taking HSC subjects that “scale well.” Not really sure what scaling is or how it affects your performance in the HSC? You’re likely not alone. That’s why we’ve put together this little guide to HSC scalings so you can make an informed decision when putting through your subject selections.

What is scaling?

Scaling is a process involving the standardisation of HSC marks so that they can be compared across subjects. These scaled marks are then converted into an aggregated UAC score, from which your ATAR is eventually derived.

Why is scaling used?

Since students throughout NSW study a different combination of subjects for their HSC, it makes it impossible to compare students’ performances against each other without some form of standardisation. After all, a student that scores a 95 in Extension 1 English is quite different to a student scoring a 95 in Standard English. Scaling is used so that no student is better or worse off by choosing certain subjects over others.

How does scaling work?

During scaling, your HSC marks essentially get adjusted according to the percentile of students you fall into for each subject. The better you perform throughout the HSC, the better you scale overall.

Which subjects are high scaling?

HSC subjects are typically grouped together in categories, ie. English subjects, Mathematics subjects, Science subjects, Humanities, and Languages, where scaling differences are illustrated most clearly.


It should come as no surprise that Extension I and II English are the highest scalings out of all of the HSC English subjects available to study, with the Advanced class coming in at a close third. If you’re quite capable of English, choosing to study at the Extension level is advantageous, since your two best units of English will be counted towards your ATAR.

If you’re not as confident at English but are deciding between Standard and Advanced, choose the latter; you may think Standard English will gain you easy marks, but the scaling potential for each subject is drastically different. A student achieving a rank in the 90th percentile will receive a mark of 31.9/50 at the Standard level, compared to a 41.9/50 at the Advanced level.


The same general rule applies to the Maths subjects as it does to the English subjects, where the Extension classes scale far better than 2 unit and General Maths. Although there is only a small difference between how Extension I and II scale – a few marks at most – you don’t even need to sit in the top percentile in order to do really well. In fact, if you rank in the 50th percentile in Extension II, you’ll end up receiving virtually the same mark as a student who ranks in the 75th percentile in Extension I.


The UAC Scaling Report 2017 shows that, out of the Sciences, Chemistry is the highest-scaling at a scaled mark of 42.8/50 for a student ranked in the 90th percentile, while Physics trails quite closely at 42.4/50 in the same percentile. While a student studying Biology will receive a mark of just 40/50 in the top 10% of students, it out-scales Senior Science by a landslide, which last year scaled down by roughly 25%.


Overall, the Humanities tend not to deviate from each other very much when scaled, however, given the wide breadth of subjects available under the area of study, certain subjects do end up scaling highly compared to others. Music 2 tends to repeatedly scale the highest; in fact, scoring in the 90th percentile in Music 2 will get you a better mark (44.9/50) than scoring in the top 1% in Food Technology (42.4/50). Other high scaling Humanities subjects include History Extension, Economics, Modern History, Legal Studies, Drama and Geography


Generally speaking, Extension and Continuers courses scale far better than Beginners Languages, however, if diving into a Beginners class is something you really want to do, then Chinese and Italian are good choices. Despite scaling down a few marks, relative to other Beginner language subjects, they tend to be easier to score well in.

Choosing your subjects

Though the scaling potential of subjects is important to keep in mind, it should not form the basis for your subject selections. Choosing high-scaling classes is a strategic tactic, but only if you’re confident that you’ll do well in the subjects you pick. All the scaling in the world cannot boost a mark to a high level if you don’t perform well in the class.

Since English is the only mandatory subject counting towards your ATAR, you want to think about which level of English to take quite carefully. Go for the highest level you think you are capable of doing; the pay off will be worth it.

As for the rest of your subjects, choose classes that align with your interests, but don’t also shoot yourself in the foot by selling yourself short – if you’re good at a particular subject, go for the harder level. If you’re choosing between subjects from different areas of study, select the one you know you’re likely to do the best in; it will give you a greater chance of ranking in a high percentile, leading to a higher overall ATAR.

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