| Centuries: | 3rd century · 4th century · 5th century |
| Decades: | 280s 290s 300s 310s 320s 330s 340s |
| Years: | 309 310 311 312 313 314 315 |
| 312 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 312 CCCXII |
| Ab urbe condita | 1065 |
| Armenian calendar | N/A |
| Bahá'í calendar | -1532 – -1531 |
| Bengali calendar | -281 |
| Berber calendar | 1262 |
| Buddhist calendar | 856 |
| Burmese calendar | -326 |
| Byzantine calendar | 5820 – 5821 |
| Chinese calendar | 辛未年十二月初六日 (2948/3008-12-6) — to —
壬申年十一月十七日(2949/3009-11-17) |
| Coptic calendar | 28 – 29 |
| Ethiopian calendar | 304 – 305 |
| Hebrew calendar | 4072 – 4073 |
| Hindu calendars | |
| - Bikram Samwat | 368 – 369 |
| - Shaka Samvat | 234 – 235 |
| - Kali Yuga | 3413 – 3414 |
| Holocene calendar | 10312 |
| Iranian calendar | 310 BP – 309 BP |
| Islamic calendar | 320 BH – 319 BH |
| Japanese calendar | |
| Korean calendar | 2645 |
| Thai solar calendar | 855 |