About this HSC Science Extension scaling calculator
This tool estimates the scaled mark you'd receive in HSC Science Extension from your raw HSC mark. It uses UAC's Preliminary Report on the Scaling of the 2025 NSW HSC, the most recent official scaling data. It is the same source behind our NSW ATAR calculator. So your Science Extension scaled mark here lines up with your full ATAR estimate there.
In 2025, Science Extension up relative to other subjects. Its average scaled mark was about 32.0/50 per unit, versus roughly 25 across the whole state, above the state average. Scaled marks are lower than HSC marks in almost every subject, because HSC marks are reported high. What matters is how a subject's scaled marks compare with others, not the size of the drop.
How Science Extension scaling works
Scaling is not a fixed bonus or penalty attached to a subject. UAC looks at how the Science Extension cohort performs across all of their subjects. It then adjusts marks so a position in Science Extension means the same as that position in any other subject.
What matters is not how the scaled mark compares to your raw mark. It is how it compares to the roughly 25 per unit that an average subject sits at. In Science Extension, the average scaled mark is about 32.0 per unit, versus roughly 25 across all subjects. So Science Extension up.
Common mistakes with Science Extension scaling
The first mistake is reading the drop from your HSC mark to your scaled mark as a penalty. It is not. Almost every subject scales below its HSC marks. HSC marks are reported high, and scaled marks sit around an average of 25 per unit.
The second is choosing a subject for its scaling alone. The best subject is the one you will score highly in. A strong mark in Science Extension beats a weak one in a higher-scaling subject, because scaling rewards your position in the cohort.