Which Units Count Towards Your ATAR? NSW HSC Rules Explained

You’ve finished the HSC with 12 units, but one subject didn’t go as well as you’d hoped. Will that subject drag down your ATAR?

Not necessarily. Under the NSW rules applying to the 2026 HSC, the Universities Admissions Centre (UAC) calculates your ATAR using your best 2 scaled units of English plus your best 8 scaled units from your remaining eligible courses. That’s 10 units altogether, even if you studied 12, 13, or more.

But there’s a catch. A subject can be left out of your ATAR calculation and still be essential for ATAR eligibility. Understanding that difference could save you from dropping the wrong course.

01The ten-unit rule: what actually counts?

Think of your ATAR calculation as having ten available places.

Two places are reserved for English. The other eight go to your strongest remaining eligible units after UAC has scaled your results.

Most HSC courses are worth two units, so they occupy two places together. Extension courses need more care because some are worth one unit, while Mathematics Extension 1 has a special counting rule when combined with Mathematics Extension 2.

There’s another detail: UAC doesn’t simply pick your ten highest HSC marks.

Your HSC mark tells you how well you performed against the standards for a particular course. UAC uses scaled marks to compare results across different courses.

The distinction matters because an HSC mark of 85 in one course isn’t automatically equivalent to an HSC mark of 85 in another.

For a fuller explanation, read How Does HSC Scaling Work? From HSC Marks to ATAR.

02Eligibility comes before choosing your best ten

Here’s a prediction worth testing.

Suppose you complete exactly ten ATAR units: four units of English, four units of Mathematics, and two units of Physics. Surely that’s enough for an ATAR?

No. You have enough units, but only three subject areas.

Under UAC’s rules, you must satisfactorily complete courses from at least four subject areas to qualify for an ATAR.

A course is a particular program, such as Mathematics Extension 2. A subject area is the broader field it belongs to, such as Mathematics. Studying several extension courses doesn’t create several subject areas.

The four ATAR eligibility requirements

For the 2026 NSW HSC, UAC requires satisfactory completion of at least:

These requirements apply to the courses you satisfactorily complete, not necessarily the particular ten units that eventually contribute to your aggregate.

This produces a slightly surprising result: your ATAR can be calculated using courses from only three subject areas, provided you completed a valid fourth subject area to establish eligibility.

Your HSC requirements are not identical

NESA determines whether you qualify for the HSC. UAC determines whether you qualify for an ATAR and calculates it.

Under NESA’s pattern-of-study rules, a standard HSC study pattern requires at least 12 units in Year 11 and 10 units in Year 12.

Both patterns must include at least six units of Board Developed courses, including two units of English, at least three courses of two units or more, and four subjects. You must also satisfy the other HSC requirements, including the HSC minimum standard.

For an ATAR, the requirement is stricter in one important respect: you need 10 eligible Board Developed units, and three of the courses must each be worth at least two units.

Board Endorsed courses can contribute towards an HSC pattern of study but cannot contribute to the ATAR aggregate.

That’s why a student can qualify for their HSC without qualifying for an ATAR.

03Can English Studies, Mathematics Standard 1, and VET courses count?

Yes, provided the relevant ATAR requirements are met, including completing the optional HSC examination where required.

You might have heard that only two units of Category B courses can count towards an ATAR. That was an older rule.

From the 2025 HSC onwards, the previous Category A and Category B distinction and its two-unit cap were removed.

For the 2026 HSC, this means courses such as English Studies, Mathematics Standard 1, and eligible VET courses can contribute together. They aren’t automatically excluded because of their former category.

There is still an exam requirement:

The optional-exam distinction is easy to miss. Simply completing a VET course, for example, doesn’t automatically produce a scaled HSC examination result that UAC can use.

For the applicable arrangements, consult UAC’s ATAR FAQs and NESA’s 2026 HSC examination guidance.

04How Mathematics and English Extension units count

Extension courses create some of the most confusing ATAR combinations.

The most important special case is Mathematics Extension 2.

Mathematics Advanced with Extension 1

If you complete Mathematics Advanced and Mathematics Extension 1, without Mathematics Extension 2, the courses have these ATAR values:

Mathematics Extension 1 with Extension 2

If you complete Mathematics Extension 2, UAC treats Mathematics Extension 1 as a two-unit course rather than one unit.

The Mathematics Extension 1 result is doubled in unit weighting for ATAR purposes.

And even if you’ve already achieved an excellent Mathematics Advanced result, that result cannot contribute once you’ve satisfactorily completed Mathematics Extension 1 and Extension 2.

This is a course-counting rule, not a bonus awarded for choosing difficult mathematics.

English Extension 1 and Extension 2

English works differently.

UAC chooses the strongest two scaled English units to satisfy the compulsory English requirement.

If your two Extension results provide the strongest English units, they can satisfy that requirement. The remaining English Advanced units are then available for selection among your best eight remaining units.

English Advanced must still be satisfactorily completed for English Extension 1 to contribute, and Extension 1 must be completed for Extension 2 to contribute.

05Should you study more than ten units?

Extra units can give you more flexibility, but they don’t automatically produce a higher ATAR.

Suppose you’re completing twelve eligible units. A weaker two-unit result might be excluded, giving you some protection if a course goes badly.

But extra units also mean more assessments, revision, and deadlines. If that workload reduces your results across several other courses, the extra subject may do more harm than good.

Here’s the useful distinction:

• UAC policy: Your aggregate uses ten scaled units under the applicable course-counting rules.
• School decisions: Your school determines which courses it can offer, how its timetable works, and its local entry or recommendation processes, subject to NESA requirements.
• Personal preparation: Your abilities, interests, workload, and study habits affect how well you can perform.
• Future university study: Individual degrees may have prerequisites, assumed knowledge, or recommended subjects that matter independently of ATAR calculation.

Don’t choose Mathematics Extension 2 or Physics simply because you’ve heard they scale well.

Scaling isn’t a fixed number of bonus marks attached to a course. It reflects the performance of the cohort studying that course, and your own result still matters.

Likewise, a school recommending particular Year 10 results before allowing enrolment in Mathematics Extension 1 isn’t the same as UAC requiring those marks for ATAR eligibility. NESA’s own course-specific requirements must still be met.

If you’re wondering whether your school’s academic results change how your ATAR is calculated, see Does Your School Affect Your ATAR? NSW HSC Explained.

Check university requirements separately

For example, the University of Sydney currently lists a mathematics prerequisite for degrees including the Bachelor of Engineering Honours.

For applicants using NSW HSC results, its published requirement can be met through Mathematics Advanced at Band 4 or Mathematics Extension 1 or 2 at Band E3, subject to the university’s admissions arrangements.

This is an example of a university requirement, not a rule that all NSW students must study Mathematics Advanced to receive an HSC or ATAR.

The requirements above were checked against the University of Sydney’s official mathematics prerequisites on 8 November 2026. If you’re applying for a later intake, check the requirements for that specific year and degree, including any approved alternative pathways.

Which HSC cohort do these rules apply to?

The aggregation and eligibility rules in this guide have been checked against UAC’s published requirements for the 2026 NSW HSC, as at 8 November 2026. The removal of the Category A/B restriction took effect from the 2025 HSC.

Students in Year 11 during 2026 are generally preparing for the 2027 HSC, while Year 10 students in 2026 are generally choosing courses for the 2028 HSC. The currently published aggregation framework is relevant to planning for those cohorts, but future students should confirm the rules again before their HSC year.

Science syllabuses also have different implementation dates:

• The Physics 11-12 Syllabus (2025) begins with Year 11 in 2027, with its first HSC examination in 2028.
• The Chemistry 11-12 Syllabus (2025) begins with Year 11 in 2028, with its first HSC examination in 2029.

Students completing Physics and Chemistry in the 2026 HSC are studying under the earlier 2017 syllabuses.

Those curriculum changes affect what students learn and are examined on, not the basic fact that each of these science courses is worth two units.

06Questions and solutions

The questions become progressively harder. Work through each course combination before reading its solution. In the later questions, watch for the difference between a unit being available, being selected, and being necessary for eligibility.

Question 1

A student satisfactorily completes the following six Board Developed courses for the 2026 HSC:

The student completes all required examinations.

a) Is the student eligible for an ATAR, assuming all other applicable requirements are satisfied?

b) How many units contribute to the ATAR aggregate?

c) If English Advanced has the lowest scaled mark, will UAC exclude it?

d) Can you determine which non-English course will be excluded from the aggregate using this information alone?

Solution 1

The student is eligible for an ATAR, and exactly ten of their twelve units will contribute.

a) The student has 12 Board Developed units, including two units of English, more than three two-unit courses, and six subject areas. The eligibility requirements are met.

b) The aggregate uses:

\[ 2+8=10\text{ units} \]

The remaining two units are excluded.

c) No. Two units of English must contribute even if they are the student’s lowest scaled units. Here, that means English Advanced.

d) No. The remaining eight units are chosen using scaled results, which haven’t been supplied.

It would be incorrect to guess that a particular subject is excluded because it is traditionally considered easier or harder.

Question 2

A student completes six two-unit courses:

• English Studies
• Mathematics Standard 1
• Hospitality (an eligible examinable VET course)
• Physics
• Chemistry
• Business Studies

All courses are satisfactorily completed, and all compulsory HSC examinations are taken. Assume the student satisfies NESA’s other HSC requirements.

The student has three optional examinations: English Studies, Mathematics Standard 1, and Hospitality.

Consider these scenarios:

a) The student sits the optional English Studies and Mathematics Standard 1 examinations, but not Hospitality. Are they ATAR-eligible?

b) Instead, they sit Mathematics Standard 1 and Hospitality, but not English Studies. Are they ATAR-eligible? Can they still qualify for the HSC?

c) If they sit all three optional examinations, can Mathematics Standard 1 and Hospitality both contribute to their ATAR, despite their former Category B classification?

Solution 2

Scenario (a) is ATAR-eligible, scenario (b) is not, and scenario (c) permits both formerly Category B courses to contribute.

a) Without the optional Hospitality examination, the student still has five examinable two-unit courses:

English Studies, Mathematics Standard 1, Physics, Chemistry, and Business Studies.

Therefore:

\[ 5\times2=10\text{ eligible units} \]

Those courses cover five subject areas and include two eligible English units. The student is ATAR-eligible.

b) Without the optional English Studies examination, the student has ten other examinable units, but no eligible English units for ATAR calculation.

The compulsory two-unit English requirement is not satisfied, so the student is not ATAR-eligible.

However, they can still qualify for the HSC. English Studies can contribute to the HSC pattern even without its optional examination, provided the remaining NESA requirements are met.

The trap is treating HSC eligibility and ATAR eligibility as identical.

c) Yes. From the 2025 HSC onwards, the former two-unit Category B limit no longer applies.

If all three optional examinations are completed, all six courses can be available for ATAR calculation.

That’s 12 eligible units. UAC will use the two English units and select the best eight remaining units according to the scaled results.

Whether Mathematics Standard 1 and Hospitality both actually appear in the final aggregate depends on those results. Neither is disqualified simply because both belonged to the old Category B classification.

Question 3

A student completes the following courses:

The student has satisfactorily completed the relevant extension requirements and examinations.

a) Explain why this student cannot receive an ATAR, even though the listed courses total ten units.

b) The student also completes two-unit Drama, creating a total of twelve eligible units. Drama receives a much lower scaled result than every other course. Can Drama be excluded from the aggregate while the student remains eligible for an ATAR?

c) If so, how many subject areas can contribute to the aggregate, and how many must have been completed?

Solution 3

The original ten-unit combination is ineligible because it contains only three subject areas. Adding Drama makes the student eligible, even if Drama contributes nothing to the aggregate.

a) The total number of units is sufficient:

\[ 4+4+2=10\text{ units} \]

However, the courses belong to only English, Mathematics, and Physics.

UAC requires four subject areas to be satisfactorily completed. The original pattern fails that condition.

b) Yes. Drama provides the fourth subject area, and the total available units become:

\[ 10+2=12\text{ units} \]

If the original ten units supply the strongest allowable scaled combination, UAC can exclude both Drama units from the aggregate.

There is no rule requiring the fourth subject area to contribute directly to the calculation.

c) The aggregate can contain units from three subject areas, although the student must have completed at least four subject areas to qualify.

This is why removing a course simply because it wasn’t included in a predicted ATAR aggregate can be dangerous. It may be the course that makes the entire study pattern eligible.

Question 4

A student is comparing two possible HSC study patterns.

In the first pattern, they complete Mathematics Advanced and Mathematics Extension 1 without Mathematics Extension 2.

In the second pattern, they also satisfactorily complete Mathematics Extension 2.

Assume all courses meet the relevant completion requirements. The table contains invented scaled results, held constant across the comparison wherever a course remains eligible.

When Mathematics Extension 2 is completed, Mathematics Extension 1 becomes worth two ATAR units, contributing twice its one-unit scaled result.

a) Calculate the illustrative aggregate without Mathematics Extension 2.

b) Calculate the illustrative aggregate with Mathematics Extension 2.

c) Explain how adding a course could lower the aggregate in this particular comparison. Does it contradict the general idea that additional eligible units provide more choices?

Solution 4

Under the stated fictional marks, adding Mathematics Extension 2 lowers the illustrative aggregate from 418 to 408 scaled-mark points because Mathematics Advanced becomes unavailable for selection.

a) Without Mathematics Extension 2

English Advanced contributes 78 scaled-mark points.

The strongest eight remaining units come from these four two-unit courses:

• Mathematics Advanced: 90
• Physics: 88
• Chemistry: 86
• Modern History: 76

Mathematics Extension 1 and Studies of Religion I together contribute:

\[ 40+34=74 \]

Their combined two units would contribute less than Modern History’s 76, so they are excluded from this selection.

Let \(A_0\) be the original aggregate.

\[ \begin{aligned} A_0&=78+(90+88+86+76)\\ &=78+340\\ &=418 \end{aligned} \]

b) With Mathematics Extension 2

Mathematics Advanced can no longer contribute.

Mathematics Extension 1 is now treated as two units:

\[ 2\times40=80 \]

The four strongest remaining two-unit contributions become Physics (88), Chemistry (86), Mathematics Extension 1 (80), and Modern History (76).

Mathematics Extension 2 contributes 70, so it is available but not selected.

Let \(A_1\) be the new aggregate.

\[ \begin{aligned} A_1&=78+(88+86+80+76)\\ &=78+330\\ &=408 \end{aligned} \]

The change is:

\[ 408-418=-10 \]

The illustrative aggregate has fallen by 10 scaled-mark points.

c) This does not contradict the usual benefit of having extra eligible units available.

Ordinarily, an additional independent course can increase your options because UAC can simply leave it out if its scaled result is lower.

Mathematics Extension 2 is different. Completing it changes the unit weighting of Mathematics Extension 1 and excludes Mathematics Advanced from the ATAR calculation.

The student isn’t merely adding an extra optional score. They’re changing the set of scores that UAC is allowed to consider.

These fictional results don’t establish that Mathematics Extension 2 is a poor choice in real life. They show why the actual course-counting rule must be considered before making predictions about the benefits of scaling.

Question 5

A high-achieving student has planned a fourteen-unit HSC program with the following hypothetical scaled results.

All courses are assumed to be eligible, satisfactorily completed, and subject to their ordinary extension-course completion rules. The student is considering alternative plans, each omitting exactly one course. No additional courses are available, and all remaining hypothetical scaled results stay unchanged.

Because Chemistry and Biology have identical scaled contributions, assume UAC initially includes Chemistry and excludes Biology when selecting the best ten units.

The student makes four proposals:

• Plan A: Remove Chemistry because Biology can replace it.
• Plan B: Remove Biology because it wasn’t originally selected.
• Plan C: Remove English Advanced because neither of its units was originally selected.
• Plan D: Remove Mathematics Extension 1 because they believe Mathematics Extension 2 has already secured their mathematics contribution.

For each plan, determine whether the student would remain ATAR-eligible and whether the original aggregate could be preserved.

You must account for the four-subject-area rule, compulsory English units, the relationship between extension courses, and the selection of the best remaining units.

Solution 5

Plans A and B both preserve ATAR eligibility and the original illustrative aggregate. Plan C destroys eligibility, while Plan D preserves eligibility but substantially reduces the aggregate.

The key is that an excluded course is not necessarily disposable, while a selected course can sometimes be replaced without losing any scaled-mark points.

Step 1: Calculate the original aggregate.

The best two English units are English Extension 1 and English Extension 2.

Their contribution is:

\[ 48+46=94 \]

The strongest eight remaining units are:

• Mathematics Extension 1: 90
• Mathematics Extension 2: 88
• Physics: 86
• Chemistry: 74

Biology has the same scaled contribution as Chemistry, so either could occupy the final two places.

The aggregate is:

\[ \begin{aligned} A&=94+90+88+86+74\\ &=432 \end{aligned} \]

The student has five subject areas: English, Mathematics, Physics, Chemistry, and Biology.

Step 2: Assess Plan A – removing Chemistry.

Plan A preserves both eligibility and the aggregate.

With Chemistry removed, Biology becomes the fourth selected two-unit course among the remaining eight units.

Because Biology contributes the same 74 scaled-mark points, the aggregate remains 432.

The student also retains four subject areas: English, Mathematics, Physics, and Biology.

Notice what’s happened. Chemistry was originally counted, but removing it doesn’t change the aggregate because an equal replacement is available.

Step 3: Assess Plan B – removing Biology.

Plan B also preserves both eligibility and the aggregate.

Chemistry remains in the original selection. The student still has four subject areas: English, Mathematics, Physics, and Chemistry.

The aggregate remains 432.

In this case, removing an excluded course really does leave everything important unchanged.

Step 4: Assess Plan C – removing English Advanced.

Plan C does not preserve ATAR eligibility.

English Advanced contributed none of the originally selected scaled-mark points, so the student might assume removing it changes nothing.

But UAC’s English Extension rules require English Advanced to be satisfactorily completed for English Extension 1 to count, and Extension 1 must be completed for Extension 2 to count.

Without English Advanced, neither Extension result can contribute under the stated study plan.

There is no other qualifying two-unit English course available. Therefore, the student fails the compulsory English requirement and cannot receive an ATAR.

This is the central trap: being excluded from the aggregate is different from being unnecessary for eligibility.

Step 5: Assess Plan D – removing Mathematics Extension 1.

Plan D can preserve ATAR eligibility but not the aggregate.

Mathematics Extension 2 cannot contribute without satisfactory completion of Mathematics Extension 1.

Removing Extension 1 therefore makes both mathematics results unavailable.

The remaining completed courses are:

• English Advanced, Extension 1, and Extension 2: 4 units
• Physics: 2 units
• Chemistry: 2 units
• Biology: 2 units

That is:

\[ 4+2+2+2=10\text{ units} \]

There are still four subject areas: English, Physics, Chemistry, and Biology. The student also retains enough two-unit Board Developed courses.

So eligibility survives.

However, the new aggregate uses the two English Extension units worth 94 points, followed by the remaining eight units: English Advanced, Physics, Chemistry, and Biology.

\[ \begin{aligned} A_{\text{new}}&=94+56+86+74+74\\ &=384 \end{aligned} \]

The aggregate falls by:

\[ 432-384=48 \]

That is a substantial loss of scaled-mark points in this fictional comparison, even though the student still qualifies for an ATAR.

Step 6: Compare the four plans.

The general lesson is more subtle than simply keeping your strongest ten units.

Before changing a study pattern, you must ask three different questions:

1. Will the remaining courses still make me eligible for an ATAR?
2. Which course results will UAC actually be allowed to use?
3. Of those available results, which ten scaled units produce the strongest permissible aggregate?

Only after all three questions are resolved can you make a sound comparison between course combinations.

07Before you change your subjects

If you’re deciding whether to keep twelve units, drop to ten, or take an Extension course, write out your proposed HSC pattern and check it against the current UAC ATAR eligibility requirements and ATAR calculation rules.

Confirm your four subject areas, identify any optional examination requirements, and check how your Extension courses change the unit values. Then discuss the proposed change with your school’s subject adviser before withdrawing from anything.

Once the study pattern is valid, the useful question changes from “Which subjects scale best?” to “Which combination lets me perform strongly while keeping the university pathways I care about open?”

That is a much better basis for choosing your HSC units than trying to guess which subject UAC will leave out.