Having extra units is not the same as dropping a course
If you complete more than 10 eligible HSC units, UAC selects your best two units of English and the best eight remaining eligible units for your ATAR aggregate. A course that is not selected can still appear in your HSC results.
Dropping a course changes your pattern of study. Do not assume that a low rank, a trial mark or an estimated ATAR tells you which units will count: UAC selects from scaled marks after the HSC, not from your school ranks alone.
There are exceptions to the general best-units rule. For example, if you satisfactorily complete Mathematics Extension 1 and Extension 2, UAC does not include Mathematics Advanced in your ATAR calculation, even if you also complete it.
Check eligibility before changing your subjects
UAC requires at least 10 units of HSC Board Developed courses, including two units of English, at least three Board Developed courses worth two units or more, and courses across four subject areas. Subject areas are not always the same as course names.
Extension, accumulated and vocational courses can involve additional rules. Check your complete pattern with your school and UAC before assuming that a change leaves you eligible for both your HSC and an ATAR.
Do not rely on older guides that limit Category B courses to two units: UAC removed the Category A and B classification from the ATAR calculation in 2025. Individual courses still need to be eligible.
Do not just stop completing the course
Speak to your year adviser or HSC coordinator about the school’s process and timing before making a change. A formal change to your enrolment is different from staying enrolled but not completing required work.
NESA explains that students must satisfy course requirements, and a non-completion determination means the course will not count towards the HSC pattern of study. The consequences depend on your individual pattern and circumstances.
Questions to take to your adviser
The best decision depends on workload, strengths, wellbeing, eligibility and any requirements for your intended university courses. A forecast can support a conversation, but it cannot guarantee which course will contribute to your ATAR.
- Would my remaining courses satisfy both HSC and ATAR requirements?
- Does this change affect any prerequisites or assumed knowledge for courses I am considering?
- What are my school’s deadlines and process for changing my enrolment?
Sources and editorial notes
ATAR Forecast guides explain school ranks, HSC results and the assumptions behind the forecasting tool, with links to NESA and UAC sources. These guides explain the process; NESA and UAC remain the official authorities.
- NESA: completing your courses in 2026
- UAC: how your ATAR is calculated
- UAC: ATAR eligibility and subject areas
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