How HSC subjects are scaled in 2026 (and what it means for your ATAR)

Every year, students hear two pieces of advice about HSC scaling. The first is "pick subjects you enjoy, scaling doesn't matter." The second is "do the highest scaling subjects you can or your ATAR will suffer." Both are partly right and mostly oversimplified. This guide explains what scaling actually does, where it matters, and how to think about subject choice without being driven by myth.

What scaling is solving for

Imagine a system where one student scores 90 in HSC Mathematics Extension 2 (one of the most demanding HSC subjects, taken almost entirely by mathematically strong students) and another scores 90 in HSC Mathematics Standard 2 (taken by a much broader cohort with a lower average ability).

If we just added their raw marks together for an ATAR aggregate, those two 90s would count the same. That is unfair: the 90 in Extension 2 was achieved against a stronger field. A student who scored 90 in Standard 2 might have scored 60 in Extension 2 had they taken it.

Scaling fixes this by computing what a student's mark in each subject says about their position relative to the strength of that subject's cohort. UAC takes everyone who sat any pair of subjects and uses their results across both to estimate how much "stronger" or "weaker" each subject's cohort was on average. Marks are then rescaled so that they are comparable.

The result: a scaled mark in any HSC subject represents the same percentile of academic strength as any other scaled mark of the same number. A 40 scaled mark per unit in English Advanced reflects the same overall academic strength as a 40 scaled mark per unit in Maths Extension 2.

What scaling does, in practice

For each HSC subject in each year, UAC publishes:

• The mean scaled mark per unit (out of 50).
• The standard deviation of scaled marks.
• The maximum scaled mark.

These numbers move slightly year to year (a few tenths of a point) but the overall pattern is stable.

A rough sense of where common subjects sit:

• Maths Extension 2: mean scaled mark around 45-47 / 50.
• Maths Extension 1: mean scaled mark around 41-43 / 50.
• Latin Extension: mean scaled mark around 44-46 / 50.
• Languages Extension: mean scaled mark around 41-44 / 50.
• Physics, Chemistry: mean scaled mark around 32-35 / 50.
• English Advanced, Maths Advanced: mean scaled mark around 32-35 / 50.
• Biology, Modern History, Economics: mean scaled mark around 28-32 / 50.
• Legal Studies, Business Studies, Studies of Religion: mean scaled mark around 25-30 / 50.
• English Standard, Maths Standard: mean scaled mark around 22-28 / 50.
• Visual Arts, Design and Technology: mean scaled mark around 26-30 / 50.
• PDHPE, Geography, Society and Culture: mean scaled mark around 24-28 / 50.

These are means. The top of the distribution in each subject scales higher; the bottom scales lower. A 90 raw in Extension 2 might scale to 49/50; a 90 raw in Maths Standard 2 might scale to 38/50.

UAC publishes the actual current-year tables every year. Look them up at the start of your senior year on the UAC website.

What the means don't tell you

The headline "Extension 2 is the highest-scaling subject" is true in mean. But the variance matters too.

• Highly-scaled subjects have a narrower distribution at the top. The strong students cluster near the top, so the difference in scaled marks between a 90 raw and a 95 raw is smaller than you might expect. A 95 in Extension 2 might be 50/50; a 90 might be 48/50. The 5-mark gap closes after scaling.
• Lower-scaled subjects have wider variance after scaling. A 95 raw in Standard 2 might be 40/50 (a significant gap above the 28-30 mean), while a 70 raw might be 18/50. The 25-mark gap stays wide.
• The bottom of a highly-scaled subject can scale very low. A 50 raw in Extension 2 scales much lower than a 50 raw in Standard 2, because the cohort assumption is that an Extension 2 student who scored only 50 is performing below where their academic baseline would predict.

The practical takeaway: scaling rewards strong performance in a strong subject, and punishes weak performance in a strong subject. It is not a free lift.

The myth of "always do the harder subject"

A common HSC myth: always pick the harder subject, because it scales higher. The maths is more nuanced.

You benefit from the harder subject if and only if your scaled mark in it would be higher than your scaled mark in the alternative. That requires you to be solidly in the middle of the harder subject's cohort or above. If you would be in the bottom 20%, the harder subject's scaling will not save you.

A rough rule that works for most students:

• If you would be likely in the top 50% of Extension 1 Maths students, take Extension 1. The scaled mark probably beats your scaled mark in Standard 2.
• If you would be likely in the top 30% of Extension 2 Maths students, take Extension 2 alongside Extension 1. The scaled mark almost certainly beats anything else.
• If you would likely be in the bottom 30% of Extension 1 Maths, you may be better off in Advanced. The scaled mark depends.

Your teachers know your cohort. Their honest read on where you would land in each option is the most useful data point you have. Ask them.

English: the unavoidable

You cannot drop English; you need at least 2 units. The question is which English:

• English Advanced scales meaningfully better than English Standard. The mean scaled mark difference is roughly 5 to 8 points per unit. For 2 units, that is 10 to 16 aggregate marks, which can shift your ATAR several points.
• English Extension 1 is a 1-unit additional subject taken alongside Advanced. It scales high (often comparable to Extension 1 Maths). If you enjoy literature and would do well, Extension is a meaningful aggregate boost.
• English Studies is a non-ATAR option for students who do not intend to use English in their aggregate. It is a perfectly legitimate path for students who are not seeking a high ATAR.

The strategic rule: take the highest level of English you can do reasonably well in. Do not stay in Standard if you could comfortably handle Advanced; that is leaving aggregate points on the table.

The most common scaling mistake I see students make is dropping out of Advanced English midway through Year 11 because the content "isn't for them." If you can hold a credit average in Advanced, the scaling benefit is too large to give up. Stick with Advanced and put the extra effort in.

Subjects whose scaling surprises students

A few subjects that scale better than students expect:

• Latin Extension and Greek Extension. Very small cohorts of highly able students. Scaling is among the highest in the HSC.
• Languages Extension (French, Chinese, Japanese, etc., at Extension level). Mean scaled marks around 41-44. Far better than Beginners level.
• Chemistry and Physics scale similarly to Maths Advanced. Often underrated by students who assume sciences are "lower-scaling."

A few that scale worse than students expect:

• Studies of Religion II (the 2-unit version). Mean scaled mark in the high 20s; widely taken in religious schools but does not give the scaling boost some students assume.
• Beginners Languages (a language you started in Year 11). Cohort is much weaker than Continuers, scales lower.
• PDHPE. Often portrayed as a "smart kid" subject by students; in fact scales moderately, around 24-28.

The point of these examples is not to say "don't do those subjects." Plenty of students take them for good reasons (interest, vocational alignment, scaling is not the only factor). The point is to make decisions with eyes open.

The 10 units that count

UAC counts your best 10 units including 2 units of English. If you do 12 units, your worst non-English 2 units drop out. This shapes the strategy of including extension subjects:

• A 1-unit extension can replace a low-scaling unit in your top 10. The extension typically scales much higher, so it lifts your aggregate.
• A second extension (e.g. English Ext 1 + Maths Ext 1 + Maths Ext 2) can replace two units if both scale higher than your weakest mandatory units.
• Adding a low-scaling 11th or 12th 2-unit subject for "safety" usually does not help. It dilutes effort without lifting aggregate.

The right number of units depends on you. Most strong students sit 11 or 12 units; some sit 10 by choice. The questions to ask:

1. Would the additional unit scale into my top 10? (If yes, take it.)
2. Can I sustain the workload across all the subjects without dropping in my best ones? (If no, fewer units focused harder is better.)

A worked decision

A student in Year 11 is choosing between:

• Path A: English Advanced (2u), Maths Extension 1 (3u total with Advanced), Maths Extension 2 (1u additional), Physics (2u), Chemistry (2u), Modern History (2u). 12 units.
• Path B: English Advanced (2u), Maths Advanced (2u), Physics (2u), Chemistry (2u), Modern History (2u), Business Studies (2u). 12 units.

Same total units. Same effort assumed. Different aggregates:

• Path A's top 10 units include the Extension 1 and Extension 2 maths, which scale very high.
• Path B's top 10 units are all 2-unit subjects with moderate scaling.

Even if the student gets the same raw marks in both paths (say, mid-80s in all subjects), Path A's aggregate is roughly 30 to 50 marks higher, which translates to several ATAR points.

But: if the student finds Extension 1 too hard and scores 60 raw, while in Path B they would have scored 88 in Maths Advanced, the picture inverts. Scaling rewards genuine ability; it does not compensate for being lost.

Practical advice

A short checklist for subject choice:

1. Take the highest level of English you can do reasonably. Always.
2. Take Maths to the highest level you can do reasonably. Most strong students should be in Extension 1 at minimum.
3. For science aspirants, Chemistry and Physics scale better than most students assume. Do not skip them for "easier" subjects unless you are clearly not going into science.
4. Pick remaining subjects for genuine interest within the scaling pattern. A subject you actually engage with will produce a better raw mark, which the scaling then operates on. A high-scaling subject you hate produces a low raw mark that scaling cannot save.
5. Talk to teachers and senior students about where you would sit in each subject's cohort. The honest answer is the highest-leverage piece of information you can get.
6. Avoid building your entire timetable on scaling. Six high-scaling subjects you barely tolerate is worse than four with two engagement subjects.

The subject choice is a strategic problem. Strategy means choosing under constraints, and your constraints include your interest, your stamina, your future plans, and your cohort competition. Scaling is one input in that puzzle, not the whole puzzle.

Make the call with the maths in mind. Then commit and study.