| Millennium: | 1st millennium |
|---|---|
| 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 |
| Assyrian calendar | 5062 |
| Bahá'í calendar | -1532–-1531 |
| Bengali calendar | -281 |
| Berber calendar | 1262 |
| English Regnal year | N/A |
| 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 | |
| - Vikram Samvat | 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 |
| Minguo calendar | 1600 before ROC 民前1600年 |
| Thai solar calendar | 855 |
Year 312 (CCCXII) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantinus and Licinianus (or, less frequently, year 1065 Ab urbe condita). The denomination 312 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.