| Millennium: | 4th Millennium BC |
|---|---|
| Centuries: | 33rd cent. BC – 32nd cent. BC – 31st cent. BC |
| Decades: | 3150s BC 3140s BC 3130s BC – 3120s BC – 3110s BC 3100s BC 3090s BC |
| Years: | 3126 BC 3125 BC 3124 BC – 3123 BC – 3122 BC 3121 BC 3120 BC |
| Gregorian calendar | 3123 MMMCXXIII |
| Ab urbe condita | 3876 |
| Armenian calendar | 2572 ԹՎ ՍՇՀԲ |
| Assyrian calendar | 7873 |
| Bahá'í calendar | 1279–1280 |
| Bengali calendar | 2530 |
| Berber calendar | 4073 |
| British Regnal year | N/A |
| Buddhist calendar | 3667 |
| Burmese calendar | 2485 |
| Byzantine calendar | 8631–8632 |
| Chinese calendar | 壬戌年 (Water Dog) 5819 or 5759 — to — 癸亥年 (Water Pig) 5820 or 5760 |
| Coptic calendar | 2839–2840 |
| Discordian calendar | 4289 |
| Ethiopian calendar | 3115–3116 |
| Hebrew calendar | 6883–6884 |
| Hindu calendars | |
| - Vikram Samvat | 3179–3180 |
| - Shaka Samvat | 3044–3045 |
| - Kali Yuga | 6223–6224 |
| Holocene calendar | 13123 |
| Igbo calendar | 2123–2124 |
| Iranian calendar | 2501–2502 |
| Islamic calendar | 2578–2579 |
| Japanese calendar | Heisei 1135 (平成１１３５年) |
| Javanese calendar | 3090–3091 |
| Juche calendar | 1212 |
| Julian calendar | Gregorian minus 22 days |
| Korean calendar | 5456 |
| Minguo calendar | ROC 1212 民國1212年 |
| Nanakshahi calendar | 1655 |
| Thai solar calendar | 3666 |
| Unix time | 36385113600–36416649599 |
The year 3123 BC