How the HSC ATAR is calculated (2026): UAC scaling, aggregate, percentile

Who does what

• NESA (NSW Education Standards Authority) runs the HSC, sets and marks the exams, moderates school assessment and reports your HSC marks. The 2026 written exams run from 13 October to 5 November and results come out on 16 December.
• UAC (Universities Admissions Centre) calculates the ATAR on behalf of NSW universities and releases it on the same day, 16 December 2026, at 9 am.

Eligibility

UAC's rules (from 2025) say you must satisfactorily complete at least 10 units of ATAR courses, including at least:

• 2 units of English;
• three courses of 2 units or greater;
• four subjects.

Before 2025 there was also a Category A/B rule (at least 8 units of Category A). UAC removed the categorisation of ATAR courses in 2025, so that rule no longer applies.

Results can be accumulated over five years. If you repeat a course, UAC uses your last satisfactory attempt.

Best 10 units

Your aggregate uses:

• your best 2 units of English; plus
• your best 8 units from everything else (which can include further English units).

With 11 or 12 units, your weakest units drop out, but English always has 2 units in. Two units of English are 20% of the aggregate.

Scaling

UAC scales raw marks, not the HSC marks on your results notice. Raw marks combine your moderated school assessment and your exam mark. NESA's HSC marks are aligned to performance bands, so UAC warns there's no one-to-one conversion from an HSC mark to a scaled mark.

The principle: a course's scaled mean is set equal to the average overall academic achievement of the students who took it. Courses taken by students who do well in all their subjects end up with higher scaled means. Scaled marks are reported per unit, out of 50.

In 2025 the highest scaled means among courses with 500+ students were Mathematics Extension 2 (43.4), Mathematics Extension 1 (39.7) and English Extension 1 (36.1). English Advanced was 32.8, Mathematics Advanced 31.9 and English Standard 20.4. See highest scaling HSC subjects for the full list.

The aggregate and the ATAR

Your aggregate is the sum of your 10 counted units of scaled marks, out of 500. UAC's 2025 report gives these conversions:

The relationship isn't linear, and it changes each year.

What the ATAR ranks you against

The ATAR runs from 0 to 99.95 in steps of 0.05. It's not a mark. It shows your position relative to the entire HSC-aged population of NSW, not just students who got an ATAR. UAC's example: an ATAR of 80.00 places you 20% from the top if every HSC-aged person in the state had been ATAR-eligible.

ATARs of 30 or below are shown as "30 or less". In 2025, 53 students received the top ATAR of 99.95.

Your HSC mark vs your scaled mark

• Your HSC mark for each course is the average of your moderated school assessment mark and your exam mark, reported against performance bands.
• Your scaled mark is UAC's version for the ATAR. It's usually lower than your HSC mark, because the average scaled mark across the whole candidature is about 25 per unit.

Where to put your effort

• Choose courses you can do well in that meet your university requirements. Scaling reflects who takes a course; your position in the course still matters most.
• Don't neglect English. Two units always count.
• A spare unit or two is insurance. An 11th or 12th unit gives you something to replace a weaker result.

For offer dates, see HSC results day and UAC offers. You can model subject mixes with the HSC ATAR calculator.

Parent or carer? Our plain-English guide for parents, The ATAR, explained for parents, covers why the ATAR is a rank rather than a mark, what scaling actually compares, how selection rank differs from the ATAR, and the other routes into university.