| Millennium: | 1st millennium |
|---|---|
| Centuries: | 6th century – 7th century – 8th century |
| Decades: | 650s 660s 670s – 680s – 690s 700s 710s |
| Years: | 681 682 683 – 684 – 685 686 687 |
| 684 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 684 DCLXXXIV |
| Ab urbe condita | 1437 |
| Armenian calendar | 133 ԹՎ ՃԼԳ |
| Assyrian calendar | 5434 |
| Bahá'í calendar | -1160–-1159 |
| Bengali calendar | 91 |
| Berber calendar | 1634 |
| English Regnal year | N/A |
| Buddhist calendar | 1228 |
| Burmese calendar | 46 |
| Byzantine calendar | 6192–6193 |
| Chinese calendar | 癸未年十二月初九日 (3320/3380-12-9) — to —
甲申年十一月二十日(3321/3381-11-20) |
| Coptic calendar | 400–401 |
| Ethiopian calendar | 676–677 |
| Hebrew calendar | 4444–4445 |
| Hindu calendars | |
| - Vikram Samvat | 740–741 |
| - Shaka Samvat | 606–607 |
| - Kali Yuga | 3785–3786 |
| Holocene calendar | 10684 |
| Iranian calendar | 62–63 |
| Islamic calendar | 64–65 |
| Japanese calendar | |
| Korean calendar | 3017 |
| Minguo calendar | 1228 before ROC 民前1228年 |
| Thai solar calendar | 1227 |
Year 684 (DCLXXXIV) was a leap year starting on Friday (link will display the full calendar) of the Julian calendar. The denomination 684 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.