The CSSE uses a statistical process called standardisation to convert raw marks into standardised scores. Each subject score is calculated using the formula: ((raw mark - mean) / standard deviation) × 15 + 100. This ensures fairness across different exam dates and age groups.

Age standardisation accounts for the developmental differences between children. A younger child competing with older peers may receive a higher standardised score for the same raw mark, reflecting their relative achievement compared to their age group.

There is no single "good" score, as different schools set their own thresholds. Total scores typically range from around 180 to 240+. We recommend checking the admissions pages of your preferred schools for their specific score profiles and requirements.

Variations occur because calculators may use different years' standardisation data or slightly different age band calculations. Always use the official means and standard deviations published by CSSE for the most accurate results.

This calculator is an independent tool designed to help parents understand the standardisation process. For official results and admissions decisions, always refer to the CSSE and your chosen schools directly.

Yes, you can enter raw marks from practice papers to estimate a standardised score. However, past paper difficulty may vary, and actual exam conditions differ. Use this as a guide only, not as a definitive prediction.