From the 2027 examination, subjects in the Singapore-Cambridge Secondary Education Certificate (SEC) carry K-prefix syllabus codes in place of the familiar four-digit O-Level codes. A G3 subject keeps the former O-Level standard and the same grade bands, so the code changes while the demand of the paper does not.
If you have seen "4052" on a past paper and "K310" on a school circular and wondered whether they are the same subject, they are. This page is the plain lookup.
The confirmed G3 codes
These are the G3 codes published for the main subjects.
| Subject | Former O-Level code | SEC G3 code | What changes in 2027 |
|---|
| English Language | 1184 | K300 | New code. The written papers move to September with Mother Tongue, and the syllabus states the oral is delivered via computer |
| Mathematics (E-Math) | 4052 | K310 | New code. Not marked as revised by SEAB |
| Additional Mathematics | 4049 | K341 | New code. Not marked as revised by SEAB |
| Physics | 6091 | K323 | New code. Not marked as revised by SEAB |
| Chemistry | 6092 | K324 | New code. Not marked as revised by SEAB |
| Biology | 6093 | K325 | New code. Not marked as revised by SEAB |
| Science (Physics, Chemistry) | 5086 | K326 | New code. Not marked as revised by SEAB |
| Science (Physics, Biology) | 5087 | K327 | New code. Not marked as revised by SEAB |
| Science (Chemistry, Biology) | 5088 | K328 | New code. Not marked as revised by SEAB |
| Chinese | 1160 | K320 | New code. One written sitting in September |
| Higher Chinese | 1116 | K355 | New code. One written sitting in September |
| Malay | 1148 | K321 | New code. One written sitting in September |
| Tamil | 1157 | K322 | New code. One written sitting in September |
"Not marked as revised" means SEAB's 2027 G3 list shows no [Revised] tag for that syllabus, so the content carries over. For every subject except English and Mother Tongue, the SEC written papers run in one common period starting in October 2027, and all SEC results come out together in January 2028.
Official syllabus PDFs: old and new codes
Each link opens the SEAB syllabus document. The four-digit codes are the 2026 O-Level versions and the K-codes are the 2027 SEC G3 versions.
- English Language: 1184 syllabus, 2026 (PDF) and K300 syllabus, 2027 (PDF)
- Mathematics: 4052 syllabus, 2026 (PDF) and K310 syllabus, 2027 (PDF)
- Additional Mathematics: 4049 syllabus, 2026 (PDF) and K341 syllabus, 2027 (PDF)
- Physics: 6091 syllabus, 2026 (PDF) and K323 syllabus, 2027 (PDF)
- Chemistry: 6092 syllabus, 2026 (PDF) and K324 syllabus, 2027 (PDF)
- Biology: 6093 syllabus, 2026 (PDF) and K325 syllabus, 2027 (PDF)
- Science (Physics, Chemistry): 5086 syllabus, 2026 (PDF) and K326 syllabus, 2027 (PDF)
- Science (Physics, Biology): 5087 syllabus, 2026 (PDF) and K327 syllabus, 2027 (PDF)
- Science (Chemistry, Biology): 5088 syllabus, 2026 (PDF) and K328 syllabus, 2027 (PDF)
G2 and G1 codes for the core subjects
Each subject has a separate code for each level. These are the 2027 G2 and G1 codes for the main subjects, with the N-Level code SEAB gives for reference.
| Subject | G2 code (former N(A) code) | G1 code (former N(T) code) |
|---|
| English Language | K200 (1190) | K100 (1195) |
| Mathematics | K210 (4045) | K110 (4046) |
| Additional Mathematics | K232 (4051) | Not offered at G1 |
| Science | K223 to K225 (5105 to 5107) | K123 (5148) |
| Chinese | K220 (1196) | K120 (1202) |
| Malay | K221 (1197) | K121 (1203) |
| Tamil | K222 (1198) | K122 (1204) |
| Computing | K237, new | K127, new |
Which SEC syllabuses are new or revised for 2027?
Most SEC syllabuses carry over with a new code. SEAB's 2027 lists mark these as new, revised or refined:
- G1 Computing (K127) and G2 Computing (K237) are new subjects. MOE says that from the 2026 Sec 3 cohort, G1 Computing replaces N-Level Computer Applications and G3 Computing replaces O-Level Computing.
- Principles of Accounts (G3 K342, G2 K233) is refined. SEAB says only the content changes, not the scheme of assessment, and the K342 syllabus is first examined in 2027. The O-Level version, 7087, was examined for the last time in 2026.
- Drama (K352) is marked revised.
- Economics (K343) and Business (K344) have new 2026 specimen papers. Their O-Level versions, 2286 and 7085, were examined for the last time in 2026.
Treat the SEAB 2027 G3 syllabus list, G2 list and G1 list as the authority for any code not shown here, and check your child's school circular, which states the exact code each subject is entered under. For the 2027 exam dates, see our guide to the Singapore-Cambridge Secondary Education Certificate (SEC) in 2027.
How to read a K-code
The letter is the system marker, not a grade. A K-prefix simply says the subject is examined under the SEC. The level a subject is taken at, G1, G2 or G3, is recorded separately on the certificate alongside the grade.
That distinction matters when you buy assessment books. A book labelled "O-Level Additional Mathematics 4049" and a book labelled "SEC Additional Mathematics K341" cover the same syllabus content for a G3 candidate. You do not need to discard material because the code on the cover is the old one.
What has not changed
- The standard. A G3 paper is set at the former Express O-Level standard.
- The grade bands. G3 grades map to the bands parents already know.
- The setting body. The SEC is set jointly by SEAB and Cambridge, the same partnership behind the O-Level.
- The content. Syllabus content carries across. Past papers under the old code remain valid practice.
What this means for past papers
This is the practical question behind the code change, and the answer is reassuring. Ten-year series and school prelim papers written under 4052 remain the correct practice material for a G3 Mathematics candidate. The topics, the paper structure and the mark allocations carry over. A student drilling 4052 papers is drilling K310 content.
The one habit worth adopting is checking the code printed on any paper your child is given, so that a G2 paper is not mistaken for a G3 one when the demand differs.
