How is ATAR calculated?
Your ATAR isn’t a percentage and it isn’t your average mark — it’s a percentile rank from 0.00 to 99.95 that shows where you sit against everyone who started Year 7 with you across your state, whether or not they went on to receive an ATAR themselves. An ATAR of 80 means you’re estimated to be in the top 20% of that group, not that you scored 80% on anything.
Every state gets there through roughly the same three steps, even though the details differ:
- Raw result. Your school assessment and external exam are combined into a raw mark or grade for each subject.
- Scaling. That raw result is adjusted against how the whole cohort taking that subject performed across all their other subjects — not against the subject’s difficulty in the abstract. A subject with a consistently strong cohort scales up; a subject with a wide spread of ability scales down.
- Aggregate → ATAR. Your best scaled subjects are summed into an aggregate, and that aggregate is ranked against the whole state’s aggregates to produce your ATAR.
Where the systems genuinely differ is which subjects count and how the aggregate is built. SACE uses your best 4 subjects in full plus half of your 5th; VCE uses your top 4 (with English compulsory) plus 10% each of your next two; HSC uses your best 10 units, English’s best 2 units included; QCE uses your best 5 subjects with a cap on non-General subjects; and WACE uses your best 4 plus a 10% bonus for certain subjects. You can see the real formula and try it yourself on the SACE ATAR calculator, VCE ATAR calculator, HSC ATAR calculator, QCE ATAR calculator, or WACE ATAR calculator.