UAC’s Preliminary Report on the Scaling of the 2025 NSW Higher School Certificate has been released, and it offers valuable insight into how each HSC course was scaled and how it contributed to ATAR calculations in 2025. Whether you’re in Year 10 choosing your HSC subjects, in Year 11 strategising for Year 12, or a parent trying to understand how your child’s subject choices affect their ATAR, this guide breaks down the data in plain language.
How HSC Scaling Actually Works
We’ll be honest: HSC scaling is genuinely complex. UAC uses a statistical process that adjusts marks based on how every student in a subject performed across all of their other subjects. There is no simple formula that converts your HSC mark to a scaled mark, and anyone who gives you a neat “HSC 80 = scaled 92” conversion is oversimplifying in a way that could mislead your subject choices.
But the underlying logic is straightforward. Here’s how it works, step by step:
- Your HSC mark is calculated. NESA combines your exam mark (50%) and your moderated school assessment mark (50%) to produce a final HSC mark out of 100 for each subject.
- UAC converts this to a scaled mark. UAC looks at how all students in your subject performed in their other subjects, and uses this to estimate where you’d rank if every HSC student in the state had taken your subject. This produces a scaled mark out of 50 per unit (or 100 for a 2-unit course).
- Your best 10 units are added up. Your best 10 units of scaled marks (including 2 compulsory units of English) are added together to create an aggregate out of 500.
- Your aggregate is ranked. Your aggregate is compared to the entire NSW age cohort — not just HSC students, but everyone who started Year 7 the same year as you — to produce your ATAR as a percentile.
Think of it this way
Think of it like this: your HSC mark tells you what grade you got on the assignment. Your scaled mark tells you where you'd rank in the class if every student in NSW had submitted the same assignment.
Imagine two students — one in a class of 30 strong students, and one in a class of 30 mixed-ability students. Both score 80%. But the student who scored 80% in the stronger class is probably a better student overall, because they achieved that mark against tougher competition. Scaling is UAC's way of accounting for that difference.
Why “Scaling Boost” Numbers Are Misleading
You’ll see some websites calculate a “scaling boost” by subtracting your HSC mark from your scaled mark. This approach is flawed, and UAC specifically warns against it in the scaling report. Here’s why:
Your HSC mark is a measure of achievement against published standards. Most students score between 50 and 100 out of 100, and the average HSC mark sits around 70–80 for most subjects. Your scaled mark is a measure of relative position — it tells UAC where you sit compared to every other student in the state. The average scaled mark across all HSC courses is approximately 50 out of 100 (or 25 per unit).
These two numbers use completely different scales. Subtracting one from the other is like subtracting your height in centimetres from your weight in kilograms — it gives you a number, but that number doesn’t mean anything useful.
What the data actually shows
The most useful way to read HSC scaling data is to compare what happens at the same percentile across different subjects. If you're a top-10% student in your subject, what scaled mark do you get? This tells you how much your strong performance is rewarded depending on which course you're in.
That's how the tables below are structured. They're based on UAC's official Table A3 from the 2025 scaling report.
2025 HSC Cohort at a Glance
Before diving into individual subjects, here’s what the 2025 HSC looked like overall:
- 60,432 students received an ATAR in 2025 — up 3,238 from 2024.
- 53 students achieved the maximum ATAR of 99.95, coming from a mix of government and non-government schools and studying 36 different courses between them.
- Median ATAR: 70.75 — slightly lower than 2024, reflecting an increase in the participation rate.
- 17.3% of students achieved an ATAR of 90.00 or above.
- Category A/B change: ATAR courses are no longer categorised as Category A or B. This meant 2,793 students included more than 2 units of former Category B courses in their aggregate — and one of these students achieved an ATAR of 96.30.
Which HSC Subjects Scaled the Strongest in 2025?
The table below shows the scaled marks at key percentiles for the highest-scaling HSC courses. All figures are per unit (out of 50), as reported in UAC’s Preliminary 2025 Scaling Report.
| Subject | Students | Scaled Mean | P99 | P90 | P50 | P25 |
| Maths Extension 2 | 3,844 | 43.4 | 49.6 | 48.3 | 44.7 | 41.5 |
| Latin Extension | 80 | 42.3 | 50.0 | 48.4 | 43.7 | 39.4 |
| Latin Continuers | 140 | 40.5 | 50.0 | 47.7 | 42.6 | 37.3 |
| Maths Extension 1 | 9,279 | 39.7 | 50.0 | 47.2 | 41.5 | 36.6 |
| French Extension | 104 | 38.9 | 50.0 | 47.0 | 38.5 | 34.5 |
| German Extension | 55 | 38.4 | 50.0 | 46.7 | 37.9 | 34.9 |
| Japanese Extension | 134 | 38.0 | 50.0 | 45.0 | 38.0 | 34.7 |
| Chinese Extension | 106 | 37.3 | 50.0 | 44.4 | 37.5 | 33.6 |
| English Extension 1 | 3,691 | 36.1 | 50.0 | 43.9 | 36.9 | 32.2 |
| Music Extension | 447 | 35.9 | 50.0 | 49.6 | 36.3 | 29.4 |
| English Extension 2 | 1,423 | 35.8 | 50.0 | 44.0 | 36.5 | 31.9 |
These subjects attract self-selected, academically strong cohorts. The scaled marks reflect the fact that students in these courses tend to perform strongly across all their other subjects — which is what drives scaling, not the difficulty of the course itself.
How Popular HSC Subjects Scaled in 2025
Most students don’t take Extension Maths or Languages. The table below shows how the most commonly chosen HSC subjects scaled in 2025 — these are the courses that form the backbone of most students’ ATAR calculations.
| Subject | Students | Scaled Mean | P99 | P90 | P50 | P25 |
| English Advanced | 26,292 | 32.8 | 46.9 | 42.6 | 33.7 | 27.7 |
| Maths Advanced | 16,809 | 31.9 | 47.5 | 42.9 | 33.2 | 25.9 |
| Chemistry | 10,369 | 32.0 | 47.6 | 43.6 | 33.9 | 25.8 |
| Physics | 8,817 | 31.0 | 47.2 | 43.0 | 32.2 | 24.0 |
| Economics | 5,741 | 31.4 | 47.1 | 43.0 | 33.0 | 25.0 |
| Biology | 20,710 | 26.2 | 45.3 | 39.9 | 26.7 | 18.0 |
| Legal Studies | 10,080 | 25.3 | 45.7 | 39.9 | 25.9 | 16.5 |
| Modern History | 10,953 | 25.0 | 46.0 | 39.2 | 25.8 | 16.6 |
| Business Studies | 20,452 | 23.9 | 45.6 | 39.2 | 23.4 | 15.1 |
| Maths Standard 2 | 31,762 | 23.3 | 42.9 | 37.3 | 23.2 | 15.1 |
| PDH&PE | 17,852 | 22.8 | 43.5 | 37.3 | 22.8 | 14.2 |
| English Standard | 33,651 | 20.4 | 39.7 | 31.5 | 20.0 | 14.5 |
How to read this table
P90 means the 90th percentile — the top 10% of students in that subject. P50 is the median — the middle student. P25 is the bottom quartile.
Look at the P90 column: a top-10% student in Chemistry gets a scaled mark of 43.6, while a top-10% student in English Standard gets 31.5. Both students are performing equally well relative to their peers — but Chemistry rewards that performance with a significantly higher scaled mark because the Chemistry cohort is academically stronger overall.
Now look at P50: the median Chemistry student (33.9) gets a higher scaled mark than the median English Standard student (20.0). This is the clearest illustration of what scaling actually does — it's not punishing English Standard students, it's reflecting the relative strength of each cohort.
Which HSC Subjects Scaled the Lowest in 2025?
The following subjects had the lowest scaled means in 2025. This doesn’t mean they’re “bad” subjects — it reflects the fact that these courses attract broader cohorts with a wider range of academic performance across their other subjects.
| Subject | Students | Scaled Mean | P99 | P90 | P50 |
| Community & Family Studies | 9,838 | 18.5 | 40.4 | 33.3 | 17.8 |
| Food Technology | 4,187 | 18.9 | 45.9 | 35.6 | 17.6 |
| Industrial Technology | 5,999 | 17.7 | 39.6 | 32.7 | 16.6 |
| Agriculture | 1,509 | 19.1 | 41.6 | 35.4 | 18.7 |
| Maths Standard 1 Exam | 3,737 | 13.9 | 34.7 | 27.7 | 12.5 |
| English Studies Exam | 2,717 | 9.0 | 25.0 | 16.4 | 8.3 |
The critical point: even in these lower-scaling subjects, top performers still achieve strong scaled marks. A student in the top 1% of Community & Family Studies received a scaled mark of 40.4 — that’s a meaningful contribution to their ATAR. The scaling “penalty” is concentrated on average and below-average performers, not on students who genuinely excel.
How HSC English Courses Scaled in 2025
English is the only compulsory HSC subject, and your best 2 units of English are automatically counted in your ATAR. This makes your English course choice one of the most consequential decisions in your HSC.
| English Course | Students | Scaled Mean | P99 | P90 | P50 | P25 |
| English Extension 1 | 3,691 | 36.1 | 50.0 | 43.9 | 36.9 | 32.2 |
| English Extension 2 | 1,423 | 35.8 | 50.0 | 44.0 | 36.5 | 31.9 |
| English Advanced | 26,292 | 32.8 | 46.9 | 42.6 | 33.7 | 27.7 |
| English EAL/D | 1,504 | 21.3 | 45.3 | 37.6 | 20.0 | 12.1 |
| English Standard | 33,651 | 20.4 | 39.7 | 31.5 | 20.0 | 14.5 |
| English Studies Exam | 2,717 | 9.0 | 25.0 | 16.4 | 8.3 | 3.6 |
The gap between English Advanced and English Standard is significant. A top-10% student in English Advanced receives a scaled mark of 42.6, while a top-10% student in English Standard receives 31.5. If you’re capable of performing well in Advanced, the scaling advantage is meaningful — and it applies to every ATAR calculation because English is compulsory.
For a full comparison of what each English course involves, see our Which HSC English Course Should You Choose? guide.
How HSC Maths Courses Scaled in 2025
| Maths Course | Students | Scaled Mean | P99 | P90 | P50 | P25 |
| Maths Extension 2 | 3,844 | 43.4 | 49.6 | 48.3 | 44.7 | 41.5 |
| Maths Extension 1 | 9,279 | 39.7 | 50.0 | 47.2 | 41.5 | 36.6 |
| Maths Advanced | 16,809 | 31.9 | 47.5 | 42.9 | 33.2 | 25.9 |
| Maths Standard 2 | 31,762 | 23.3 | 42.9 | 37.3 | 23.2 | 15.1 |
| Maths Standard 1 Exam | 3,737 | 13.9 | 34.7 | 27.7 | 12.5 | 6.6 |
The scaling difference between Maths courses is the most dramatic in the entire HSC. The median Maths Extension 2 student (44.7) receives a scaled mark nearly double that of the median Maths Standard 2 student (23.2). If you’re a capable maths student, moving up one level — from Standard 2 to Advanced, or from Advanced to Extension 1 — has a significant impact on your ATAR, provided you can maintain strong performance at the higher level.
Should You Choose Subjects Based on Scaling?
Choosing a subject only because it scales well can be risky. High-scaling subjects typically come with heavier workloads, more technical complexity and stronger competition. Students generally achieve better outcomes when they choose subjects they genuinely enjoy and feel confident in, even if those subjects scale less favourably.
Here’s the reality check:
Scaling only helps if you perform well in the subject
A student who scores in the top 25% of Business Studies (P75 scaled mark: 32.6) gets a higher scaled mark than a student who scores in the bottom 25% of Chemistry (P25 scaled mark: 25.8). Every year, students achieve ATARs of 95+ and even 99+ with combinations that include Business Studies, Legal Studies, PDH&PE and other moderately-scaling subjects — because they score exceptionally well in them.
Bottom line: Your ranking within a subject matters far more than which subject you choose. A high raw score in any subject will serve your ATAR well.
The Category A/B Change in 2025
A significant change in 2025 was the removal of the Category A/B distinction for ATAR courses. Previously, students could include a maximum of 2 units of Category B courses (mostly VET and Life Skills subjects) in their ATAR aggregate. This restriction has been removed.
In 2025, 2,793 students included more than 2 units of former Category B courses in their aggregates, with 66 students including 8 such units. While the average ATAR of these students was 43.80, one student achieved an ATAR of 96.30 and 27 achieved ATARs exceeding 80.00. This opens up genuine ATAR pathways for students on VET-heavy programs that didn’t exist before.
Tips for Maximising Your ATAR in 2026
- Play to your strengths. Pick subjects you enjoy and naturally perform well in. High raw performance nearly always beats relying on scaling alone.
- Understand scaling, but don’t be ruled by it. Know how your subjects typically scale so you can set realistic expectations, but don’t choose a subject you’ll struggle in just because it scales well.
- If you’re strong in maths, go as high as you can. The scaling difference between Maths Standard 2, Advanced and Extension 1 is the largest in the HSC. If you can handle the step up, it makes a meaningful difference.
- English Advanced matters. Since English is compulsory and counts in every ATAR, the gap between Standard and Advanced scaling is worth paying attention to. If you’re capable of performing well in Advanced, the scaling benefit is real.
- Seek support early. A tutor can help you build confidence and improve performance in your chosen subjects — which is the single most effective way to improve your ATAR, regardless of scaling.
- Use UAC’s ATAR Compass. UAC’s free ATAR Compass tool lets you enter your expected HSC marks and estimate your ATAR based on historical scaling data. It’s the most reliable estimator available because it’s built by the organisation that actually calculates ATARs.
Frequently Asked Questions
Scaling is the process UAC uses to adjust your HSC marks so that students can be fairly compared across different subjects. It works by estimating where you’d rank if every HSC student in NSW had taken your subject. Subjects with stronger cohorts (where students also perform well in their other subjects) tend to scale up, while subjects with broader cohorts tend to scale down. Scaling reflects cohort strength, not subject difficulty.
No. Scaling reflects the academic profile of the students who choose each subject, not the quality or value of the subject itself. Students who excel in lower-scaling subjects still achieve strong ATARs. Choosing a subject you enjoy and perform well in is more important than chasing scaling numbers.
Your HSC mark doesn’t change — NESA reports your HSC mark as-is on your Record of Achievement. Scaling produces a separate scaled mark that UAC uses internally to calculate your ATAR. In subjects with lower-scaling cohorts, the scaled mark will typically be lower than the HSC mark, but this is a feature of the measurement system, not a penalty on your reported results.
Not necessarily. If you’re performing well in the subject and it’s contributing to your best 10 units, dropping it could hurt your ATAR by removing a strong result. The question is always whether your performance in the subject (relative to the cohort) produces a scaled mark that makes it into your best 10 units. If it does, scaling direction is secondary.
No — and UAC specifically warns against using one. For each HSC mark there is a range of possible scaled marks depending on the underlying raw marks. The percentile tables in this guide show the patterns, and UAC’s ATAR Compass tool provides the best available estimates based on 5 years of historical data. But no table can give you an exact conversion.
The UAC Preliminary Report on the Scaling of the 2025 HSC is available now. A more detailed report will be released by UAC in May 2026.
Get Expert HSC Support on Learnmate
Learnmate’s research shows that 70% of students achieving ATARs of 99+ engage one or more tutors. Whether you’re aiming to maximise your performance in high-scaling subjects like Maths Extension or Chemistry, or you want to push for a top result in English Advanced, Biology or Business Studies, an HSC tutor on Learnmate can provide the targeted feedback and exam technique coaching that makes the difference. Research from Evidence for Learning confirms that one-to-one tuition adds the equivalent of five additional months of academic progress.
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