Short answer: HSC scaling is the step that makes marks in different NSW courses comparable before they are added up for the ATAR. Each course is scaled from how its own students did across all their HSC courses. The scaled marks are worked out after the exams, in the year you finish, and they are not reported to students, so nobody can give you your scaled marks or your ATAR in advance.
This guide explains the two different sets of marks, what scaling uses, how the 10 units are picked, and what you can work out yourself. For the mark on your HSC results, use the HSC Mark and Band Calculator.
Two sets of marks: your HSC marks and the ATAR inputs
Students in NSW meet two different processes, run by two different bodies, and mixing them up causes most of the confusion.
- HSC marks (NESA). These are the marks on your results. For each course, NESA averages your aligned exam mark and your moderated assessment mark, and rounds half marks up. The mark then sits in a band, from Band 6 at 90 to 100 down to Band 1 at 0 to 49 for a 2 unit course.
- Scaled marks (for the ATAR). These feed the ATAR. NESA's Understanding your HSC results says UAC uses the moderated assessment marks and the exam marks taken before alignment, not the HSC marks you see. Those are then scaled.
So a Band 6 in a course does not turn into a fixed amount of ATAR. The band tells you the standard you reached. Scaling decides how much the course adds to your aggregate.
Worked example 1: the HSC mark you see
Made-up example. In one course a student has an exam mark of 76 and an assessment mark of 71. The average is (76 + 71) ÷ 2 = 73.5, and NESA rounds half marks up, so the HSC mark is 74, Band 4. That 74 is what appears on the results. It is not the number that goes into scaling, because UAC starts from the marks before alignment.
What scaling does
UAC's page How your ATAR is calculated gives the principle: you should be neither advantaged nor disadvantaged by the courses you choose. Marks in different courses cannot be compared directly, so each course is scaled so its mean and spread fit the marks its students earn across all their HSC courses.
Three things follow from that, all on UAC's page:
- Your scaled mark in a course depends on your position in that course and on the course's scaled mean.
- Scaled marks are calculated in the year the courses are completed.
- Scaled marks are not reported to students.
The NSW ATAR itself is calculated by the Technical Committee on Scaling on behalf of the NSW Vice-Chancellors' Committee. GradeCat gives no scaling formula and no scaled means here, because the pages in our research do not publish them for students.
Which 10 units count
The ATAR is built from an aggregate of scaled marks in 10 units: the top 2 units of English plus the top 8 other units, ranked by scaled mark. You also need to complete at least four subject areas. For a course you repeat, the latest satisfactory attempt counts. Most courses are 2 units, and the extension courses add the rules below.
- English: English Advanced is 2 units, and Extension 1 and Extension 2 are 1 unit each. The highest-scaled English courses fill the 2 English units.
- Mathematics: up to 4 units of calculus-based Mathematics can count. Extension 1 counts as 1 unit with Advanced, or as 2 units with Extension 2, with its mark doubled.
- All three Mathematics courses: a student who completes Advanced, Extension 1 and Extension 2 has the Advanced result left out.
Worked example 2: counting the units
Made-up example. A student takes English Advanced (2 units), Mathematics Advanced (2), Mathematics Extension 1 (1), Chemistry (2), Physics (2), Economics (2) and Legal Studies (2).
- Units in all: 2 + 2 + 1 + 2 + 2 + 2 + 2 = 13.
- English Advanced fills the 2 English units.
- That leaves 11 other units, and only 8 of those units count, so 3 units are left out.
Which 3 drop out depends on the scaled marks, which the student will never see. That is why a raw mark table cannot tell you which of your courses is "counted".
Worked example 3: Mathematics Extension 2
Made-up example. A student completes Mathematics Advanced, Extension 1 and Extension 2. Under UAC's rule the Advanced result is left out. Extension 1, paired with Extension 2, counts as 2 units with its mark doubled, and Extension 2 adds 2 units, so 2 + 2 = 4 units of Mathematics, the most that can count.
From aggregate to ATAR
The aggregate is not your ATAR. UAC says the ATAR ranks you among your whole age group: all 16 to 20-year-olds in NSW. That is why it is a rank and not a mark out of 100.
If you want an estimate, UAC's ATAR Compass uses the past five years of scaling data. UAC calls it a guide only, says it is less precise for very low marks and small courses, and it covers the NSW HSC only.
What you can work out yourself
- Each HSC mark and band, once you know the exam and assessment marks.
- How many units you have, and whether you meet the four subject areas.
- Which English and Mathematics units can count under the rules above.
What you cannot work out is your scaled marks or your ATAR. Any ATAR given before results day is an estimate.
HSC scaling FAQ
Does scaling lower my marks?
Scaling does not produce the HSC marks on your results. NESA works those out from your aligned exam mark and your assessment mark, while scaling works on a separate set of marks used for the ATAR.
Can I see my scaled marks?
No. UAC says scaled marks are not reported to students.
Is scaling the same every year?
No. UAC says scaled marks are calculated in the year the courses are completed, so they are worked out again each year.
How many units count toward the ATAR?
10 units: the top 2 units of English and the top 8 other units, with at least four subject areas completed.
Who calculates the NSW ATAR?
The Technical Committee on Scaling, on behalf of the NSW Vice-Chancellors' Committee.
Related tools and guides
- HSC Mark and Band Calculator: your HSC mark and band from the exam and assessment marks.
- WAM vs GPA in Australia: how averages work once you are at university.
- All tools for Australia
- GradeCat home: grade and GPA tools for other countries.
Sources
- NSW Education Standards Authority (NESA): Determining HSC results (opened 4 November 2026)
- NSW Education Standards Authority (NESA): Understanding your HSC results (opened 4 November 2026)
- UAC: How your ATAR is calculated (opened 4 November 2026)
- UAC: ATAR Compass (opened 4 November 2026)
A unit count or HSC mark worked out here is an estimate, not an official result. NESA's and UAC's own results come first. Found a mistake? Tell us.