Can a Lower-Scaling Subject Still Count Towards a High ATAR?

Yes. A subject with a reputation for lower scaling can still count towards a high ATAR. What matters is the scaled mark you achieve in that subject and whether it makes it into your ATAR aggregate.

A subject does not automatically become a poor choice because it scales less favourably on average. Equally, choosing a subject known for strong scaling does not guarantee a better ATAR. Understanding the difference between these two ideas will help you make a much better decision about your HSC subjects.

## The difference between doing well in a subject and how it scales

Imagine you receive an HSC mark of 85 in two different subjects. Does that mean you've achieved exactly the same level of academic performance in both?

Not necessarily.

An HSC mark tells you about your result in that particular course. Scaling accounts for the academic achievement of the students taking that course across their other HSC subjects.

This matters because an 85 in one subject does not necessarily represent the same relative academic performance as an 85 in another.

The Universities Admissions Centre (UAC) explains that scaling adjusts the mean and distribution of marks in each course to reflect the overall achievement of the students studying it. The aim is to prevent students from being advantaged or disadvantaged simply because they chose one pattern of study rather than another.

In practical terms, a course taken by many students who achieve highly across their other HSC subjects will generally have a stronger scaling profile. However, you still need to achieve a strong result within that course to receive a high scaled mark.

[IMAGE: Two contrasting HSC classroom scenes showing students undertaking different subjects, with a visual comparison of the idea that identical HSC marks can represent different relative academic performances. Keep the emphasis on the students' performance within their respective courses rather than suggesting that one subject is inherently harder.]

### What UAC's scaling example actually tells us

UAC provides an illustrative comparison of students who achieved results at the 90th percentile in different HSC courses.

| Subject | HSC mark | Scaled mark |
|---|---:|---:|
| Ancient History | 89.0 | 75.6 |
| Biology | 87.0 | 78.4 |
| Business Studies | 90.0 | 77.4 |
| Society and Culture | 90.0 | 76.2 |
| Physics | 91.0 | 86.8 |
| English Standard | 81.0 | 62.6 |

Source: [UAC - How your ATAR is calculated](https://uac.edu.au/future-applicants/atar/how-your-atar-is-calculated).

There are two important observations here.

First, Physics has a substantially higher scaled mark than the other listed courses, even though its HSC mark is not dramatically higher. This reflects the different scaling profiles of the courses.

Second, the table does not mean that every Physics student will receive a high scaled mark, or that every Ancient History student will receive a low one. It illustrates results at a particular percentile, not a guaranteed conversion between HSC and scaled marks.

UAC explicitly explains that your position within your course matters. A high HSC mark in a subject with a lower scaling profile can still produce a worthwhile scaled mark, particularly when your performance in that course is strong.

The important distinction is this:

- **Scaling reputation:** How a course's marks tend to be adjusted based on the academic achievement of its students.
- **Your performance:** How well you perform in that course relative to the other students taking it.
- **Your ATAR contribution:** Whether your resulting scaled mark is high enough to be included in your 10-unit aggregate.

These are related, but they are not interchangeable.

## How a lower-scaling subject can count towards your ATAR

Your NSW ATAR is calculated using an aggregate of scaled marks from 10 units of HSC courses.

The calculation uses:

- Your best 2 units of English.
- Your best 8 units from your remaining eligible courses.

This is important because your English units are compulsory in the calculation, even if they are not your strongest results. Your other subjects compete for the remaining eight units.

If you study exactly 10 eligible units, all 10 units contribute, provided you meet the ATAR eligibility requirements. If you study more than 10 units, some results may be left out.

[IMAGE: A clear visual showing the NSW ATAR aggregate: two compulsory English units alongside eight selected units from other eligible HSC courses. Include additional unselected units outside the aggregate, making it clear that selection is based on scaled results rather than subject reputation.]

The key point is that UAC does not simply select subjects according to their scaling reputation. It selects the eligible units that produce the required aggregate.

### Worked example: Can Business Studies count instead of Physics?

Consider a student studying 12 units:

| HSC course | Units |
|---|---:|
| English Advanced | 2 |
| Mathematics Advanced | 2 |
| Physics | 2 |
| Biology | 2 |
| Business Studies | 2 |
| Visual Arts | 2 |
| **Total** | **12** |

Assume the student meets all ATAR eligibility requirements.

The student must include their two English units. The remaining eight units are selected from the other 10 units.

Suppose the student's scaled results in the five non-English courses rank from highest to lowest as follows:

1. Mathematics Advanced
2. Biology
3. Business Studies
4. Visual Arts
5. Physics

In this hypothetical example, the first four courses contribute their eight units. Physics is left out.

Notice what happened: Business Studies, despite having a less favourable scaling reputation than Physics, contributes to the student's ATAR. Physics, despite its stronger scaling reputation, does not.

This is not a prediction about the scaling of either subject. It demonstrates how individual performance and the selection of the best eight units interact.

The student would not benefit from choosing Physics purely because of its reputation if they were likely to achieve a substantially weaker result in it.

01What scaling does not do

There are three misconceptions worth clearing up before you choose your subjects.

1. Scaling does not change your position within a subject

Suppose you finish ahead of another student in Physics. Scaling will not reverse your position and put that student above you.

UAC’s technical report confirms that scaling preserves the ranking of students within each course. It changes the numerical marks to make results from different courses comparable, but it does not rearrange the students within a course.

This is important because you cannot rely on scaling to rescue a weak performance. Doing well in your chosen subject still matters.

2. Scaling is not a fixed bonus

You might see a table showing that Mathematics Extension 2 or Physics has a high scaled mean. It is tempting to treat that as a permanent advantage.

But UAC recalculates scaling each year. The process reflects the demonstrated academic achievement of that year’s students taking each course.

A subject’s previous scaling results are useful background information, but they are not a reliable prediction of what your own mark will become.

Scaled marks are also not reported to students, so you cannot calculate your exact scaled mark simply by applying a fixed conversion to your HSC mark.

3. Scaling does not measure how difficult a subject is

This is another common mistake.

Students sometimes assume that a subject must scale highly because its content is difficult. However, UAC’s scaling model does not simply award extra marks for difficult content.

It considers the demonstrated academic achievement of the students taking each course. A subject’s scaling profile reflects its candidature, not a universal difficulty rating.

That is why choosing the hardest-looking combination of subjects is not automatically the best ATAR strategy.

For a more detailed explanation of the process, see How Does HSC Scaling Work? From HSC Marks to ATAR?.

02Check your ATAR eligibility before choosing subjects

There is another distinction that matters: a course contributing to your HSC does not automatically mean it contributes to your ATAR.

NESA sets the requirements for completing the HSC, including the required pattern of study. UAC sets the separate eligibility requirements for receiving a NSW ATAR and calculates the ATAR aggregate.

For NSW HSC students, UAC’s current eligibility requirements include:

• At least 10 units of eligible ATAR courses.
• At least 2 units of English.
• At least three Board Developed courses of 2 units or more.
• Courses from at least four subject areas.

Your ATAR is then calculated using your best 2 units of English and your best 8 remaining units.

You need to pay attention to the difference between a course and a subject area. For example, English Advanced and English Extension 1 are different courses, but they belong to the same subject area. Taking several courses from English and Mathematics does not automatically satisfy the four-subject-area requirement.

Also, Board Endorsed courses can contribute towards your HSC but do not contribute towards your ATAR. Check the classification of a course rather than assuming that every subject available at your school is ATAR-eligible.

Sources: UAC ATAR eligibility and calculation and NESA’s current pattern of study rules.

An important change from 2025

You might still come across advice saying that only two units of Category B courses can contribute towards your ATAR.

That advice is outdated.

UAC removed the Category A and Category B classification system from 2025 onwards. The previous restriction limiting Category B contributions to two units was removed at the same time.

For students completing the HSC from 2025 onwards, the old Category B limit should not be used when planning an ATAR aggregate. You must still satisfy the current ATAR eligibility requirements, and the courses must be eligible ATAR courses.

This is a good reason to be careful with older ATAR calculators, subject-selection guides, and advice written under previous rules.

Source: UAC’s October 2025 technical report on ATAR calculation.

For a closer look at how the 10-unit aggregate works, see Which Units Count Towards Your ATAR? NSW HSC Rules Explained.

03University prerequisites are a separate consideration

Suppose you want to study engineering at university. You might discover that your preferred degree recommends or requires Mathematics Extension 1 and Physics.

Does that mean every NSW student must study those subjects to be eligible for an ATAR?

No. University admission requirements and NSW HSC requirements are different things.

Universities set their own admission requirements for individual degrees. Three terms are particularly important:

The distinction can make a real difference to your subject choices.

For example, UNSW’s 2027 Domestic Undergraduate Student Guide lists Mathematics Extension 1 and Physics as assumed knowledge for several Bachelor of Engineering (Honours) specialisations.

The University of Sydney takes a different approach across its degrees. Its published admission criteria explain that the advanced mathematics prerequisite was removed for many degrees from 2025, but remains for particular courses, including Engineering and Advanced Computing.

These examples show why you should investigate the actual degree rather than relying on broad statements such as “you need Physics for engineering”.

Sources: UNSW 2027 Domestic Undergraduate Student Guide and University of Sydney admission criteria through UAC.

Before dropping a subject because of its scaling reputation, check whether it is important for your intended university course. A subject that contributes less to your ATAR aggregate might still be valuable for meeting an admission prerequisite or developing the knowledge you need at university.

On the other hand, do not assume that a university’s assumed knowledge requirement is a statewide NESA requirement. It applies to the preparation expected for that particular university course.

04What control does your school have over subject selection?

Your school may have its own rules about which subjects it offers and who can enrol in particular courses.

For example, a school might:

• Not offer a particular HSC course because of staffing or timetable limitations.
• Use previous academic results when advising students about advanced courses.
• Have a local selection process when more students request a course than the school can accommodate.
• Recommend a different subject combination based on a student’s current academic preparation.

These decisions can affect which subjects you are able to study at your school. However, they do not change UAC’s scaling calculations.

It helps to separate five different considerations:

If someone tells you that a particular subject is not suitable for your ATAR, ask them to explain exactly why.

Are they referring to a NESA requirement, a UAC eligibility rule, a university prerequisite, or your school’s own selection policy?

Those are very different reasons. A school recommendation based on your current performance is not proof that a subject will scale poorly for you.

05How should you actually choose your HSC subjects?

Rather than trying to predict which subjects will scale best, consider the following factors in order.

1. Check your university options

If you have a degree in mind, investigate its prerequisites and assumed knowledge for the year you intend to commence.

Do not sacrifice an important prerequisite simply because another subject has a more attractive scaling reputation.

If you are unsure about your future degree, consider which subjects will keep relevant options open.

2. Consider where you can perform strongly

Think about your existing academic strengths.

For example:

• Do you enjoy solving unfamiliar mathematical problems?
• Are you comfortable explaining scientific concepts and interpreting experimental results?
• Do you prefer extended writing and analysing evidence?
• Are you more consistent in subjects where assessment involves practical work, problem-solving, or written responses?

A subject that suits your abilities and interests may allow you to achieve a stronger result than a subject you select purely for its scaling reputation.

This does not guarantee a particular scaled mark. It simply gives you a more sensible basis for choosing.

3. Look at the actual course content

Do not choose a subject based on its name or reputation alone.

Look at the syllabus, assessment requirements, and the type of thinking involved. Make sure you understand what you will be studying for two years.

This is especially important when reading older subject guides. NSW science syllabuses are being replaced on different schedules.

For example:

• The 2025 Physics syllabus begins implementation for Year 11 in 2027, with the first HSC examination under the new syllabus in 2028.
• The 2025 Chemistry syllabus begins implementation for Year 11 in 2028, with the first HSC examination under the new syllabus in 2029.

This means students entering Year 11 in 2027 will study the new Physics syllabus but the existing 2017 Chemistry syllabus. Older Module 1-8 Physics and Chemistry resources describe the 2017 courses and should not be mistaken for the replacement syllabuses.

Check the relevant NESA Physics syllabus or NESA Chemistry syllabus for the correct implementation dates.

4. Think about your overall workload

Your subject combination matters beyond the individual scaling profiles.

Taking an extra subject may give you more units from which UAC can select your best results. However, studying more units does not automatically give you a higher ATAR.

The extra workload may also reduce the time available for your other subjects. If your performance suffers across several courses, the additional subject might not provide the benefit you expected.

A balanced combination that allows you to perform consistently is generally a more sensible starting point than choosing subjects solely to maximise the number of units available.

5. Consider whether you actually want to study the subject

You will spend a significant amount of time learning, revising, completing assessments, and preparing for examinations.

Interest is not the only factor in academic performance, but it can influence how consistently you engage with a course.

If you enjoy the content, understand its demands, and can see its relevance to your future plans, that is a meaningful reason to choose it.

You do not need to justify every subject choice through scaling.

06What does a high ATAR actually measure?

One final point is worth understanding: your ATAR is a rank, not a percentage or an HSC mark.

UAC reports the ATAR on a scale from 0.00 to 99.95. An ATAR of 90.00 means you have performed better than 90% of the same-age NSW population.

Your ATAR comes from your aggregate of scaled marks, which is then used to rank you against the relevant cohort.

This explains why concentrating on one subject’s scaling profile is not enough. Your overall aggregate matters.

A lower-scaling subject can contribute to that aggregate, but it needs to produce a competitive scaled mark relative to your other eligible units.

07Questions and solutions

Question 1

A student completes exactly 10 units of eligible ATAR courses. These include 2 units of English and 2 units of a subject with a relatively low scaling reputation.

Can UAC automatically leave that subject out of the ATAR calculation because it scales less favourably?

Solution 1

No. The subject cannot be excluded simply because of its scaling reputation.

UAC uses the best 2 units of English and the best 8 remaining eligible units. If the student has exactly 10 eligible units, all 8 non-English units must contribute to the aggregate.

The important qualification is that the course must be ATAR-eligible and the student must satisfy the eligibility requirements.

Scaling still affects the numerical value of the subject’s contribution. A lower scaled mark can reduce the aggregate compared with a stronger result, but that is different from the subject being automatically excluded.

Question 2

UAC’s illustrative scaling example shows the following results for students at the 90th percentile:

• Ancient History: HSC mark of 89.0, scaled mark of 75.6.
• Biology: HSC mark of 87.0, scaled mark of 78.4.

A student argues that the Ancient History result must be worth more because the original HSC mark is higher.

Is that conclusion correct? Explain why or why not.

Solution 2

No. In UAC’s example, Biology produces the higher scaled mark despite having the lower HSC mark.

The mistake is assuming that HSC marks from different courses can be compared directly. They cannot, because each course has a different candidature and mark distribution.

UAC’s scaling process accounts for the overall academic achievement of students taking each course. The scaled mark is therefore not determined by the HSC mark alone.

The figures also do not establish that Biology will always scale better than Ancient History. They are an illustration of the scaling process, not a prediction for another cohort.

Question 3

Two students, Mia and Leo, study the same HSC course.

Mia receives a higher HSC mark than Leo. However, Leo believes that the course’s scaling will push his result above Mia’s.

Could this happen?

Solution 3

No. Scaling does not reverse the ranking of students within the same course.

UAC’s technical report explicitly states that although scaled marks differ from the original marks, the ranking of students within a course remains unchanged.

Scaling adjusts the numerical marks to make results comparable across different courses. It does not rearrange the students within a particular course.

Leo might receive a scaled mark that is higher than his original HSC mark, depending on the course’s scaling, but he cannot overtake Mia through scaling alone if Mia was ranked above him in that course.

Question 4

A student preparing for the 2027 HSC is choosing their subjects.

Someone tells them that they should avoid a particular course because it was previously classified as Category B, and only two units of Category B courses can contribute to an ATAR.

Is this advice still correct?

Solution 4

No. The two-unit Category B restriction was removed from the 2025 ATAR rules.

UAC removed the Category A and Category B classifications from 2025 onwards. Therefore, the previous restriction on Category B contributions no longer applies to the 2027 HSC cohort.

However, this does not mean that every HSC course automatically contributes to an ATAR.

The student must still check whether the course is an eligible ATAR course and whether their overall subject combination satisfies UAC’s eligibility requirements.

If the course is eligible, its contribution depends on the scaled result and the selection of the best eight remaining units.

The lesson is to use the rules that apply to your own HSC cohort rather than relying on old subject-selection advice.

Question 5

Consider the following argument:

“UAC says scaling is designed to prevent students from being advantaged or disadvantaged by their subject choices. But its example shows that a student at the 90th percentile in Physics receives a scaled mark of 86.8, while a student at the 90th percentile in Ancient History receives only 75.6. Surely this proves that Physics is always the better subject for an ATAR?”

Is this reasoning correct? Explain how the different scaled marks can coexist with UAC’s stated aim of fair scaling. Also explain whether a student taking Ancient History could still use it towards a high ATAR.

Solution 5

No. The argument confuses a system designed to account for differences between courses with a promise that the same percentile in every course must produce the same scaled mark.

UAC’s scaling model considers the demonstrated overall academic achievement of the students taking each course. It does not simply convert a student’s percentile position into an identical scaled mark across every subject.

The Physics and Ancient History cohorts have different overall academic profiles. Consequently, the scaled marks associated with the same percentile position can differ.

There are three constraints that matter here.

First: the strength of the candidature matters.

A student ranked highly in a course is competing against the other students taking that course. UAC considers those students’ demonstrated academic achievement across their HSC subjects when determining the course’s scaling profile.

A high percentile position is therefore not enough to predict an identical scaled mark in every subject.

Second: scaling preserves the ranking within each course.

A student who performs better than another student in Ancient History will retain that higher position after scaling. The process adjusts the numerical marks rather than changing the order of students.

It also does not assume that Physics is intrinsically more difficult than Ancient History. Scaling is recalculated each year to reflect the academic achievement of the relevant course candidatures.

Third: your ATAR depends on the complete aggregate, not the scaling profile of one subject.

A student taking Ancient History can still have its scaled mark included in their ATAR if it is selected among their best 8 remaining eligible units.

For example, if that student’s Ancient History result is stronger after scaling than their result in another eligible course, Ancient History may contribute while the other course is excluded.

The reverse can also happen. A student might study Physics, achieve a weaker result than expected, and find that another subject produces a stronger scaled mark.

The apparent contradiction disappears once you distinguish between a course’s scaling profile, an individual’s performance, and the final aggregate.

UAC’s aim is to make different patterns of study comparable. It is not to guarantee identical scaled marks for identical percentile positions or to promise that choosing a particular subject will produce a higher ATAR.

That is why a lower-scaling subject can still be a perfectly sensible part of a high-ATAR subject combination.

08Policy and cohort information

Information checked: 8 November 2026

This article covers NSW HSC students seeking an ATAR through UAC. The eligibility and scaling rules reflect UAC’s published NSW requirements at the date of writing.

The university admission example refers specifically to the 2027 UNSW domestic undergraduate guide. Admission prerequisites, assumed knowledge, selection ranks, and adjustment schemes can change between admission years. Always check the university’s published requirements for your intended year of entry.

For the official rules, consult:

• UAC – How your ATAR is calculated
• UAC – ATAR frequently asked questions
• UAC – NSW ATAR technical report, October 2025
• NESA – Assessment Certification Examination rules

The practical takeaway is simple: don’t start by asking which subject scales best. Start by checking that your subjects meet the relevant requirements, keep your university options open, and give you a realistic opportunity to perform strongly.

A lower-scaling subject can absolutely contribute towards a high ATAR. The next decision is making sure you understand its syllabus, assessment requirements, and the preparation needed to achieve a strong HSC result. That is a much better basis for choosing your subjects than relying on scaling reputations alone.