PSLE T-Score to AL Score Conversion: How to Translate Old Results

Quick Answer: There is no direct formula for converting a T-score to an AL band because the two systems measure fundamentally different things — T-scores are relative (cohort-dependent), while AL bands are absolute (raw-mark-dependent). However, MOE published a rough mapping by simulating the 2018 cohort's results through both systems simultaneously, giving parents and schools a practical reference for understanding how old cut-off points relate to new PSLE Score ranges.

Many parents who experienced the T-score era want to translate their own old results — or an older sibling's results — into the new AL framework. While a precise conversion is mathematically impossible, understanding the relationship between the two systems helps make sense of secondary school indicative score ranges and gives context to conversations with relatives who still think in T-score terms.

PSLE T-score to AL score conversion refers to the approximate mapping between Singapore's old norm-referenced scoring system and the current standards-referenced AL system, which MOE derived by running a single cohort's raw marks through both frameworks — it is a practical reference tool, not a mathematical formula, because T-scores depend on cohort distribution while AL bands depend only on raw marks.

Why Direct Conversion Is Impossible

The T-score formula, T = 50 + 10 × (raw mark − cohort mean) ÷ standard deviation, contains two variables — the cohort mean and the standard deviation — that change every year. The same raw mark of 85 could produce a T-score of 62 in a difficult paper year and 56 in an easy paper year. Since the AL band is based purely on the raw mark (85 is always AL2), there is no one-to-one mapping.

If you only know someone's old T-score, you cannot determine their raw mark without also knowing that year's cohort mean and standard deviation for each subject — data MOE does not publicly release. This is why any "T-score to AL converter" you find online is approximate at best.

The MOE Mapping: How Indicative AL Ranges Were Created

To produce the indicative PSLE Score ranges published for each secondary school, MOE took the 2018 P6 cohort's actual raw marks and processed them through both systems. For each student, they calculated both the T-score aggregate and the PSLE Score (by mapping raw marks to AL bands). They then looked at each secondary school's 2018 intake under the T-score system and recorded the range of PSLE Scores those same students would have received under the AL system.

This produced the indicative AL score ranges that parents use today when choosing secondary schools. It is worth emphasising that these are indicative — based on one cohort, one year's paper difficulty, and one year's school popularity patterns. They provide a rough guide, not a guarantee.

Practical Mapping Table: What a T-Score Roughly Means in AL Terms

Based on MOE's published simulation data and secondary school posting patterns, here is a rough equivalence guide:

This table should be treated as a rough orientation tool, not a precise converter. The mapping is broad because the two systems measure different things. A T-score of 238 does not "equal" a specific PSLE Score — it falls somewhere in a range.

What This Means When Comparing Siblings' Results

Parents sometimes ask: "My older child scored 245 under the T-score. What PSLE Score should my younger child aim for to match that?" The answer is not a specific number but a performance tier. An older sibling who achieved a T-score of 245 was roughly in the top 10–15% of their cohort. Under the AL system, a PSLE Score of 8 to 10 represents a similar tier, depending on subject balance.

Rather than comparing scores across systems, compare what the scores achieved: did both children gain access to schools that fit their interests and learning needs? The AL system was designed partly to move conversations away from score comparison and toward this more meaningful question.

Using the Conversion to Understand Secondary School Options

The most practical use of T-score-to-AL mapping is interpreting secondary school cut-off points. If you recall that a particular school had a T-score cut-off around 240 in the old system, the indicative AL range for that school today is likely around 8 to 12. This helps you assess whether your child's expected PSLE Score puts that school within realistic reach.

MOE updates indicative AL score ranges annually based on the most recent posting exercise. Always use the latest published ranges rather than relying on T-score memory or third-party websites that may use outdated data.

FAQ

Can I convert my own old PSLE T-score to see what AL band I would have gotten?

Not with precision. You would need your exact raw marks for each subject and that year's cohort mean and standard deviation for each paper — data that was never provided on result slips. You can use the rough mapping table above to estimate which performance tier your T-score placed you in, but you cannot determine your exact AL equivalent.

Are the indicative AL score ranges the same as T-score cut-off points?

No. Indicative AL score ranges are broader and represent the spread of PSLE Scores among students posted to a school in a given year. The old T-score cut-off point was the lowest aggregate score admitted. Under AL, with only 29 possible scores, a school's intake may span three to six different PSLE Scores across different streams, and the range includes everyone, not just the lowest score.

Does a lower PSLE Score always mean a better result?

Yes — a lower PSLE Score is better (PSLE Score 4 is the best possible, 32 the highest). This can be counterintuitive for parents used to the T-score where higher was better. The PSLE Score is the sum of AL numbers, and AL1 is the best, so the lowest sum wins. This is one of the most common points of confusion when converting between systems.

Why does the same T-score map to different PSLE Scores in different sources?

Because T-scores are cohort-relative and AL bands are absolute, any mapping is approximate. Different sources may use different reference cohorts, different assumptions about subject balance, or different rounding methods. MOE's own indicative ranges are the most authoritative reference, and even they are presented as ranges rather than precise equivalents.

Summary

Converting T-scores to AL bands is about understanding performance tiers, not finding an exact equivalent. The two systems measure different things, and MOE's indicative AL score ranges — based on a real-cohort simulation — are the most reliable reference available. For parents supporting a child through PSLE today, the more productive focus is on understanding the AL band boundaries, helping your child target specific bands in each subject, and using the latest indicative school score ranges for posting decisions. iWorld Learning's PSLE English programmes help students build the consistent performance across all four papers that the AL system rewards. Visit us at Tanjong Pagar or Somerset to learn more.