Your HSC mark and scaled mark are different numbers
Scaling does not rewrite the HSC mark NESA reports to you. UAC scales raw HSC marks to help compare students taking different combinations of courses, then uses scaled marks in the ATAR aggregate. A scaled mark is a calculation input, not a replacement HSC result.
It is common for a scaled mark to be below the reported HSC mark in a course, but that alone does not mean the course is a bad choice or that a student has lost marks from their certificate.
Why can a scaled mark go down?
UAC scaling reflects the academic performance of the students taking a course, as observed through their results across courses. It is not a judgement about whether a subject is easy, difficult, useful or worthy. A high raw mark in a course with a lower scaled mean can produce a scaled mark below the raw mark, while another course can move in the opposite direction.
Scaling is recalculated each year. A course’s past scaling is not a promise about its scaling for the cohort that will sit the HSC this year.
What should students do with this?
Choose courses that fit your strengths, interests and future requirements. Focus on learning and achieving the strongest result you can in each course rather than trying to predict a future scaling table. Scaling is intended to make different course patterns comparable, not to reward a subject label on its own.
If comparing online estimates, check whether they show an HSC mark, a scaled mark or an ATAR. Those are different outputs and should not be read interchangeably.
Sources and editorial notes
Founder of ATAR Forecast. These 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: how HSC results are determined
- UAC: how your ATAR is calculated
- UAC: report on the scaling of the 2025 NSW HSC
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An experimental estimate, not an official ATAR calculation.