404 (CDIV) was a leap year starting on Friday of the Julian calendar, the 404th year of the Common Era (CE) and Anno Domini (AD) designations, the 404th year of the 1st millennium, the 4th year of the 5th century, and the 5th year of the 400s decade. As of the start of 404, the Gregorian calendar was 1 day ahead of the Julian calendar, which was the dominant calendar of the time.

Millennium: 1st millennium
Centuries: 4th century5th century6th century
Decades: 370s  380s  390s  – 400s –  410s  420s  430s
Years: 401 402 403404405 406 407
404 in other calendars
Gregorian calendar404
CDIV
Ab urbe condita1157
Assyrian calendar5154
Balinese saka calendar325–326
Bengali calendar−189
Berber calendar1354
Buddhist calendar948
Burmese calendar−234
Byzantine calendar5912–5913
Chinese calendar癸卯(Water Rabbit)
3100 or 3040
    — to —
甲辰年 (Wood Dragon)
3101 or 3041
Coptic calendar120–121
Discordian calendar1570
Ethiopian calendar396–397
Hebrew calendar4164–4165
Hindu calendars
 - Vikram Samvat460–461
 - Shaka Samvat325–326
 - Kali Yuga3504–3505
Holocene calendar10404
Iranian calendar218 BP – 217 BP
Islamic calendar225 BH – 224 BH
Javanese calendar287–288
Julian calendar404
CDIV
Korean calendar2737
Minguo calendar1508 before ROC
民前1508年
Nanakshahi calendar−1064
Seleucid era715/716 AG
Thai solar calendar946–947
Tibetan calendar阴水兔年
(female Water-Rabbit)
530 or 149 or −623
    — to —
阳木龙年
(male Wood-Dragon)
531 or 150 or −622

Events change