| Millennium: | 1st millennium |
|---|---|
| Centuries: | 6th century – 7th century – 8th century |
| Decades: | 590s 600s 610s – 620s – 630s 640s 650s |
| Years: | 618 619 620 – 621 – 622 623 624 |
| 621 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 621 DCXXI |
| Ab urbe condita | 1374 |
| Armenian calendar | 70 ԹՎ Հ |
| Bahá'í calendar | -1223 – -1222 |
| Bengali calendar | 28 |
| Berber calendar | 1571 |
| Buddhist calendar | 1165 |
| Burmese calendar | -17 |
| Byzantine calendar | 6129 – 6130 |
| Chinese calendar | 庚辰年十二月初四日 (3257/3317-12-4) — to —
辛巳年十一月十三日(3258/3318-11-13) |
| Coptic calendar | 337 – 338 |
| Ethiopian calendar | 613 – 614 |
| Hebrew calendar | 4381 – 4382 |
| Hindu calendars | |
| - Bikram Samwat | 677 – 678 |
| - Shaka Samvat | 543 – 544 |
| - Kali Yuga | 3722 – 3723 |
| Holocene calendar | 10621 |
| Iranian calendar | 1 BP – -0 BP |
| Islamic calendar | 1 BH – -0 BH |
| Japanese calendar | |
| Korean calendar | 2954 |
| Thai solar calendar | 1164 |