| Grade/Year | Age range | Phase |
| Junior infants | 4-5 | |
| Senior infants | 5-6 | |
| First class/Standard I | 6-7 | Primary/first-level |
| Second class/Standard II | 7-8 | Primary/first-level |
| Third class/Standard III | 8-9 | Primary/first-level |
| Fourth class/Standard IV | 9-10 | Primary/first-level |
| Fifth class/Standard V | 10-11 | Primary/first-level |
| Sixth class/Standard VI | 11-12 | Primary/first-level |
| Seventh class | 12-13 | Secondary/second-level |
| Eighth class | 13-14 | Secondary/second-level |
| Ninth class | 14-15 | Secondary/second-level |
| Tenth class (Year 10) | 15-16 | Secondary/second-level |
| Eleventh class (Year 11) | 16-17 | Secondary/second-level |
| Twelfth class (Year 12) | 17-18 | Secondary/second-level |
Bold = compulsory