How accurate is this ATAR calculator?

The estimate is directional, not official. Real ATARs depend on multiple factors the calculator doesn't see: your school's cohort strength relative to the WA average, the gap between school internals and final exam marks, exact subject combination, and bonus points. We use it to check whether a student is on track for their target ATAR, not to make hard claims.

Where do you get the scaling numbers used in this calculator?

The scaling factors are based on multi-year SCSA scaling reports, averaged for stability. Specific year-on-year scaling shifts slightly; we use directional averages so the estimate stays sensible across cohorts. For year-specific accuracy, always cross-reference SCSA's most recent published scaling tables.

Can I save my estimate or come back to it later?

The calculator runs in your browser without saving or sending data. To revisit your estimate, either bookmark this page with your inputs (the URL doesn't persist them) or screenshot the result. Email yourself a copy if it's useful, we don't store anything.

Does the calculator account for ATAR bonus points?

No. Bonus points (e.g., for Languages other than English, regional bonuses, equity programs) are not factored in. Your real ATAR with bonus points may be 1 to 5 points higher than the calculator suggests. Check the TISC website for bonus-point rules that apply to your specific situation.

Free ATAR Calculator · Estimate Your ATAR

Your subjects & current school marks

Pick four to six subjects. Enter your current school average as a percentage (e.g. 78). Leave a row blank to skip it.

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How accurate is this? The estimate uses publicly published SCSA scaling tables and the typical relationship between school internals and final ATARs. It's directional, not official. Your school's cohort, exam vs internal weighting, and unscaled vs scaled mark gap will all move the real number. We use it to spot whether a student is on track for their target, never to make hard ATAR claims.

How TISC actually calculates your final ATAR

Your real ATAR is a percentile rank within the WA Year 12 ATAR-eligible cohort, not a fixed score. Here's what goes into it that this calculator can't see:

1. Final subject mark (50% school + 50% exam): For most ATAR subjects, your final mark is half your school internal assessment and half your written exam. A student averaging 80% at school but 70% on the exam ends with 75%, not 80%. This calculator uses your school average as a stand-in for the final mark, so it can over-estimate if your exam performance lags.
2. SCSA standardisation (cohort-difficulty scaling): SCSA scales each subject's raw marks against the cohort that took it that year. Subjects taken by stronger cohorts (Maths Specialist, Methods, Chemistry, Physics) scale up; subjects with weaker cohorts (Maths Applications, some humanities) scale down. The factors shift slightly year to year, so we use multi-year averages here.
3. Top-4 Tertiary Entrance Aggregate (TEA): TISC sums your best 4 scaled marks (maximum 430 from 2017 onward). The TEA is your raw position within the ATAR-eligible cohort, not yet your ATAR.
4. The participation function (TEA → ATAR): Your ATAR is your percentile rank within the entire school-leaving age cohort, not just ATAR-eligible students. TISC uses a Harrison-Hyndman cubic-spline participation function (endorsed by ACTAC in 2016) to translate TEA into ATAR. Because only ~43% of WA school-leavers sit ATAR exams, students at the top of the candidature get pulled even higher: a candidate at the 87th percentile of the ATAR-eligible cohort lands at ATAR 98.3, not 87. This explains why mid-pack TEAs can still produce strong ATARs.
5. Bonus points (added to TEA, not the ATAR directly): TISC adds 10% of your best LOTE (Language Other Than English) scaled score, plus 10% of your scaled scores in Maths Methods and Maths Specialist if you take them. Regional and equity bonuses can also apply. Bonus points typically lift a real ATAR by 1–5 points.
6. Cohort effect (school strength): Your school's cohort affects how your school marks translate to scaled marks. At schools with consistently high exam performance (e.g. Hale, Perth Modern, MLC, Christ Church), an 80% internal often becomes a higher scaled mark than the same 80% at a school whose cohort exam-performs below the WA average. The calculator can't see your school.
7. Subject combination quirks: You can't double-count similar subjects in your top 4 (e.g. Maths Methods and Maths Specialist both count, but TISC has rules around overlapping content). Some VET and General courses don't count toward ATAR. If you're unsure whether a subject contributes, check SCSA's course list.

For the official process, see TISC's ATAR explanation and SCSA's published scaling reports. This page exists to help you set realistic targets, not replace TISC's calculation.

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Your subjects & current school marks

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