How L1R5 and A-Level rank points actually work
Every year around now a student shows me a grade slip and asks "so what is my L1R5?" and I do the sum on the back of it. Here is the sum, once, so you can do it yourself, and a calculator that writes the working out beside every number.
Grades are points, and lower is better
Each O-Level grade is worth a number: A1 is 1, A2 is 2, B3 is 3, B4 is 4, C5 is 5, C6 is 6, D7 is 7, E8 is 8, F9 is 9. Your aggregate is a sum of those numbers, so a smaller total is a better result. The best raw L1R5 anyone can have is 6 (six A1s), and JC admission is usually quoted as a net L1R5 of 20 or better.
What L1R5 counts
L1R5 is one language plus five relevant subjects, six in all. It is built in this order:
- L1: English.
- R1: your best Humanities subject (Combined Humanities, Geography, History, Literature).
- R2: your best Maths or Science subject.
- R3: your best remaining subject from either of those two groups.
- R4 and R5: your best two of whatever is left, any subject at all.
Anything after that is dropped. It does not hurt you and it does not help you, which matters when you decide where to spend the last few weeks.
Worked example: an O-Level slip
Say the grades are English B3, Chinese B4, E Maths A2, A Maths B4, Combined Science B3, Combined Humanities A2, Principles of Accounts C5.
- L1 English: 3
- R1 best Humanities: Combined Humanities, 2
- R2 best Maths/Science: E Maths, 2
- R3 best of the rest of those groups: Combined Science, 3 (A Maths at 4 loses)
- R4 and R5 best two remaining: A Maths 4 and Chinese 4
Raw L1R5 = 3 + 2 + 2 + 3 + 4 + 4 = 18. Accounts at C5 is dropped, so a better Accounts grade would have changed nothing here; a better A Maths or Chinese grade would have taken a point straight off.
Bonus points come off the top
Bonus points are subtracted from the raw score. CCA can give up to 2, and Higher Mother Tongue or a Mother Tongue-related subject can give up to 2 more, with the exact conditions set out in the year's admission exercise booklet. The student above with 2 CCA points has a net L1R5 of 16. Check the current MOE rules for your cohort rather than a forum post, because the conditions change and the difference between 20 and 21 is a different school.
Poly uses ELR2B2 instead
Polytechnic admission uses English plus two relevant subjects plus your best two others, five subjects, and the usual line is 26 or better. Which subjects count as "relevant" depends on the course group, so the calculator's version, which treats Maths, Science and Humanities as relevant, is an estimate. The course pages on the poly websites list the real ones.
A-Level rank points, the 70-point scale
From the 2026 admission year the local universities work out rank points out of 70 rather than 90, and the calculator has both scales. On the new one an H2 grade is worth A 20, B 17.5, C 15, D 12.5, E 10, S 5, U 0, and an H1 grade is worth half of that. The base score is your best three H2 content subjects plus H1 General Paper: 20 + 20 + 20 + 10 = 70 at most.
Your fourth content subject and H1 Mother Tongue are the interesting part. Each is added only if it improves your score after rebasing: the raw total is divided by its own maximum and scaled back to 70. So a weak fourth subject is simply left out, and a strong one is counted. Project Work is a pass or fail with no points, but a pass is still required.
Worked example: when the fourth subject helps
H2 Chemistry A (20), H2 Maths A (20), H2 Physics B (17.5), General Paper C (7.5). Base = 65.
Add H1 Economics at A (10): raw 75 out of a possible 80, rebased (75 ÷ 80) × 70 = 65.63. That is higher than 65, so Economics counts and the rank points are 65.63.
Now swap Economics for a C (7.5): raw 72.5 out of 80, rebased 63.44. Lower than 65, so it is left out and the score stays at 65. Same student, same three H2s; the fourth subject only ever helps.
Use it to decide where the hours go
One grade band is one point, and a band is roughly five percent of marks. Put the two subjects sitting in R4 and R5 into the grade calculator, set a target, and it tells you how many points you are short and which grade steps would close the gap. It picks the Singapore O-Level system from your browser region, or you can choose it, and it also does IB, GPA, ATAR, GCSE and CBSE. Everything stays on your device, no sign-in. Bands and rules differ between schools and years, so treat the numbers as an estimate and check with your school before you plan around them.