400 BC

Millennium: 1st millennium BC
Centuries:
Decades:
Years:
400 BC in various calendars
Gregorian calendar400 BC
CD BC
Ab urbe condita354
Ancient Egypt eraXXVIII dynasty, 5
- PharaohAmyrtaeus, 5
Ancient Greek era95th Olympiad (victor
Assyrian calendar4351
Balinese saka calendarN/A
Bengali calendar−992
Berber calendar551
Buddhist calendar145
Burmese calendar−1037
Byzantine calendar5109–5110
Chinese calendar庚辰年 (Metal Dragon)
2298 or 2091
    — to —
辛巳年 (Metal Snake)
2299 or 2092
Coptic calendar−683 – −682
Discordian calendar767
Ethiopian calendar−407 – −406
Hebrew calendar3361–3362
Hindu calendars
 - Vikram Samvat−343 – −342
 - Shaka SamvatN/A
 - Kali Yuga2701–2702
Holocene calendar9601
Iranian calendar1021 BP – 1020 BP
Islamic calendar1052 BH – 1051 BH
Javanese calendarN/A
Julian calendarN/A
Korean calendar1934
Minguo calendar2311 before ROC
民前2311年
Nanakshahi calendar−1867
Thai solar calendar143–144
Tibetan calendar阳金龙年
(male Iron-Dragon)
−273 or −654 or −1426
    — to —
阴金蛇年
(female Iron-Snake)
−272 or −653 or −1425
Map of the world in 400 BC.
Celtic influence in Europe 400 BC (blue and purple).

Year 400 BC was a year of the pre-Julian Roman calendar. In the Roman Republic, it was known as the Year of the Tribunate of Esquilinus, Capitolinus, Vulso, Medullinus, Saccus and Vulscus (or, less frequently, year 354 Ab urbe condita). The denomination 400 BC for this year has been used in Europe since the early medieval period, when the Anno Domini calendar era became prevalent there.