| Centuries: | 4th century · 5th century · 6th century |
| Decades: | 370s 380s 390s 400s 410s 420s 430s |
| Years: | 401 402 403 404 405 406 407 |
| 404 by topic | |
| Politics | |
| State leaders - Sovereign states | |
| Birth and death categories | |
| Births - Deaths | |
| Establishment and disestablishment categories | |
| Establishments - Disestablishments | |
| Gregorian calendar | 404 CDIV |
| Ab urbe condita | 1157 |
| Armenian calendar | N/A |
| Bahá'í calendar | -1440 – -1439 |
| Berber calendar | 1354 |
| Buddhist calendar | 948 |
| Burmese calendar | -234 |
| Chinese calendar | 3040/3100-12-3 (癸卯年十二月初三日) — to —
3041/3101-11-14(甲辰年十一月十四日) |
| Coptic calendar | 120 – 121 |
| Ethiopian calendar | 396 – 397 |
| Hebrew calendar | 4164 – 4165 |
| Hindu calendars | |
| - Vikram Samvat | 459 – 460 |
| - Shaka Samvat | 326 – 327 |
| - Kali Yuga | 3505 – 3506 |
| Holocene calendar | 10404 |
| Iranian calendar | 218 BP – 217 BP |
| Islamic calendar | 225 BH – 224 BH |
| Japanese calendar | |
| Korean calendar | 2737 |
| Thai solar calendar | 947 |