How this calculator works

1. Raw score — exact (SATAC method)

Each Stage 2 subject is graded on the SACE 15-point scale: A+ = 15 down to E- = 1, N = 0. School-based components contribute up to 70% (max 10.5/15), and the external assessment up to 30% (max 4.5/15).

• · Internal contribution = sum over components of gradeValue × componentWeight
• · External contribution = (mark / maxMark) × externalWeight × 15
• · Raw subject score = internal + external, max 15

These calculations follow the SATAC SACE/NTCET fact sheet for tertiary entry exactly. Numbers in the breakdown page are deterministic — feed in the same grades and you get the same raw score.

2. Scaled score — estimated

SATAC's actual scaling algorithm is not public. We do not, and cannot, reproduce it exactly. Instead, we use a calibrated statistical model with per-subject parameters:

• · Standardise the raw score: z = (raw − meanRaw) / sdRaw
• · Convert to a percentile via the standard normal CDF
• · Map back to the scaled distribution: scaled = refMeanScaled + z × refSdScaled
• · Add a top-end nonlinear bonus to differentiate elite scores
• · Clamp to a per-subject maximum (e.g. 20.0 for Specialist Maths)

We also report a likely range and a confidence label (high/medium/low) per subject. Subjects with stronger calibration data (e.g. Specialist Maths, English, Methods) get higher confidence.

3. Aggregate → ATAR — exact lookup

Aggregate is the best 4 scaled subjects + 0.5 × the 5th, capped at 90. The ATAR is then read from the official SATAC 2025 aggregate-to-ATAR table — only valid 0.05 increments are returned.

4. Calibration loop

You can submit your actual ATAR anonymously after results are released. We use that data to refine subject scaling profiles. The goal is for our estimated scaling layer to drift towards reality each year.