21 BC

Millennium: 1st millennium BC
Centuries:
Decades:
Years:
21 BC in various calendars
Gregorian calendar21 BC
XXI BC
Ab urbe condita733
Ancient Greek era189th Olympiad, year 4
Assyrian calendar4730
Balinese saka calendarN/A
Bengali calendar−613
Berber calendar930
Buddhist calendar524
Burmese calendar−658
Byzantine calendar5488–5489
Chinese calendar己亥年 (Earth Pig)
2677 or 2470
    — to —
庚子年 (Metal Rat)
2678 or 2471
Coptic calendar−304 – −303
Discordian calendar1146
Ethiopian calendar−28 – −27
Hebrew calendar3740–3741
Hindu calendars
 - Vikram Samvat36–37
 - Shaka SamvatN/A
 - Kali Yuga3080–3081
Holocene calendar9980
Iranian calendar642 BP – 641 BP
Islamic calendar662 BH – 661 BH
Javanese calendarN/A
Julian calendar21 BC
XXI BC
Korean calendar2313
Minguo calendar1932 before ROC
民前1932年
Nanakshahi calendar−1488
Seleucid era291/292 AG
Thai solar calendar522–523
Tibetan calendar阴土猪年
(female Earth-Pig)
106 or −275 or −1047
    — to —
阳金鼠年
(male Iron-Rat)
107 or −274 or −1046

Year 21 BC was either a common year starting on Monday, Tuesday or Wednesday or a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a leap year starting on Sunday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Lollius and Lepidus (or, less frequently, year 733 Ab urbe condita). The denomination 21 BC 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.