How many units in Year 11 and Year 12? In NSW you need at least 12 units of Preliminary courses in Year 11 and at least 10 units of HSC courses in Year 12. Your ATAR is then calculated from just 10 units: your best 2 units of English plus your best 8 units from everything else. Those three numbers, 12, 10 and 10, drive almost every subject-selection decision a senior student makes.
They are also where families get tangled, because HSC eligibility, ATAR eligibility and the ATAR calculation are three separate rule sets that happen to use similar-sounding numbers. Here is each one, straight from NESA and UAC.
What is a unit in the HSC?
A unit is NESA’s measure of course size. One unit represents roughly 60 hours of study per year and is worth 50 marks. Most courses are 2 units, which is why a typical Year 12 student takes five or six subjects to reach 10 to 12 units.
Extension courses are the exception: they are 1 unit each and are marked out of 50 rather than 100. That is why English Extension 1, Mathematics Extension 1, History Extension and Science Extension are described as adding an eleventh or twelfth unit to a pattern.
How many units do you need in Year 11?
At least 12. NESA requires a Preliminary pattern of study comprising at least 12 units, which usually means six 2-unit courses. Most students take 12 or 13 units in Year 11 knowing they will drop to 10 or 11 for the HSC year.
Taking 13 units in Year 11 is common and sensible. It gives you a course to drop if one subject turns out to be a poor fit, without putting your HSC eligibility at risk.
How many units do you need in Year 12?
At least 10. NESA’s pattern of study rules require an HSC pattern comprising at least 10 units. Alongside that unit total, your pattern must include:
- 2 units of a Board Developed course in English
- at least 4 more units of Board Developed courses
- at least 3 courses of 2 or more units
- at least 4 subjects
There is also a cap most students never hit: a maximum of 6 units of Preliminary Science courses and 7 units of HSC Science courses can count towards HSC eligibility.
How many units count towards your ATAR?
Ten, and only ten. The UAC Report on the Scaling of the 2025 NSW HSC states that the ATAR is based on an aggregate of scaled marks in 10 units of ATAR courses, made up of your best 2 units of English plus your best 8 units from the remaining courses.
This is the rule that makes an eleventh or twelfth unit worth considering. If you study 12 units, the two weakest units simply fall out of the aggregate. You are not penalised for them, and you gain two more chances at a strong result. The trade-off is study time, which is finite.
What do you need to be eligible for an ATAR?
Under the rules that applied to the 2025 HSC, a student must have satisfactorily completed at least 10 units of ATAR courses, including at least 2 units of English, at least three courses of 2 units or greater, and at least four subjects.
One rule change catches almost everyone out. UAC removed the Category A and Category B classification of ATAR courses in 2025. The old requirement to have at least 8 units of Category A courses no longer applies. Many school handbooks, forum posts and tutoring blogs still describe the Category A and B system, so check a current source before you plan a pattern around it.
Do English Studies, Maths Standard 1 and VET courses count?
They can, but only if the student sits the optional examination. English Studies, Mathematics Standard 1 and VET courses contribute to ATAR eligibility and to the ATAR calculation only where the student enrols in the appropriate additional examination course and completes the examination.
Without that examination, the course still counts towards the HSC credential but does nothing for the ATAR. If a university offer is in the plan, that examination is not optional in practice.
How many units should you actually take?
Here is how the common patterns compare in practice.
| Pattern | Year 11 | Year 12 | Best for |
|---|---|---|---|
| Minimum | 12 units | 10 units | Students carrying heavy commitments outside school, or who need every hour for their core subjects |
| Standard | 12 to 13 units | 10 to 11 units | Most students. One spare unit gives room for a weak result to drop out of the aggregate |
| Extended | 13 to 14 units | 12 units | Students taking two Extension courses who are already comfortably on top of their workload |
An illustrative example. Consider a student taking English Advanced, Mathematics Advanced, Biology, Business Studies and Modern History. That is 10 units, and every single unit counts towards the ATAR, so one poor course drags the whole aggregate. Add English Extension 1 as an eleventh unit and the picture changes: the weakest unit in the pattern now drops out, and the student has a buffer against a subject that goes badly. That buffer is worth more than most families realise, and it costs one unit of study time rather than a whole extra subject.
The counter-argument is real. An extra unit taken by a student who is already stretched can lower five other results. Add units for insurance only if the rest of the pattern is genuinely under control.
Can you drop a subject in Year 12?
Yes, provided you stay at or above 10 units and your pattern still satisfies the English and course-count requirements. Dropping from 12 units to 10 partway through Year 12 is common and usually happens after the half-yearly assessments.
Be deliberate about it. Dropping a course you are ranked highly in, to protect one you are struggling in, can cost more scaled marks than it saves. Look at your internal ranks first. Our explainer on how HSC internal ranks affect your ATAR covers why rank matters more than raw mark here.
Does the number of units change how subjects scale?
No. Scaling is applied per unit, and a course’s scaled mean reflects the overall academic strength of the students in it, not how many units you personally carry. Adding an eleventh unit does not lift or lower the scaling of anything else in your pattern.
What it does change is which units reach your aggregate. That is why students often pair a lower-scaling but reliable subject with a higher-scaling one. Our guides to the highest-scaling HSC subjects and how to read the HSC scaling report explain how to weigh that up with real figures rather than staffroom folklore.
When should you finalise your unit pattern?
Year 10 subject selection sets the Preliminary pattern, and most NSW schools run that process across Term 3, so it is decided now for students starting Year 11. The Year 12 pattern is confirmed at the end of the Preliminary year, once you have real results to look at rather than predictions.
Use the Year 11 yearly examinations as your evidence. A student sitting in the bottom third of a course after a full Preliminary year rarely turns it around in the HSC year while carrying everything else. Our HSC and ATAR subject selection guide works through the whole decision, and what ATAR most students actually get is worth reading before you set a target.
If you would like a second opinion on your child’s unit pattern before it is locked in, our tutors do this every year with families across NSW. Book a first lesson today, or read how our HSC tutoring in Sydney programme is structured.
Frequently asked questions
How many units do you need in Year 11 in NSW?
At least 12 units of Preliminary courses. Most students take 12 or 13 units in Year 11, usually six 2-unit courses, so that they have room to drop a subject before the HSC year.
How many units do you need in Year 12?
At least 10 units of HSC courses, including 2 units of a Board Developed course in English, at least 4 more units of Board Developed courses, at least 3 courses of 2 or more units, and at least 4 subjects.
How many units count towards the ATAR?
Ten. UAC uses your best 2 units of English plus your best 8 units from your remaining ATAR courses. Any units beyond that are excluded from the aggregate.
Can you do 13 units in Year 11?
Yes. Thirteen units is a common Preliminary pattern and gives you a course to drop if one subject is not working out, without putting HSC eligibility at risk.
Is there still a Category A and Category B rule for ATAR courses?
No. UAC removed the categorisation of ATAR courses in 2025, so the previous requirement for at least 8 units of Category A courses no longer applies. Older guides that still describe it are out of date.