| Centuries: | 7th century - 8th century - 9th century |
| Decades: | 750s 760s 770s - 780s - 790s 800s 810s |
| Years: | 778 779 780 - 781 - 782 783 784 |
| 781 by topic | |
| Politics | |
| State leaders - Sovereign states | |
| Birth and death categories | |
| Births - Deaths | |
| Establishment and disestablishment categories | |
| Establishments - Disestablishments | |
| Gregorian calendar | 781 DCCLXXXI |
| Ab urbe condita | 1534 |
| Armenian calendar | 230 ԹՎ ՄԼ |
| Bahá'í calendar | -1063 – -1062 |
| Berber calendar | 1731 |
| Buddhist calendar | 1325 |
| Burmese calendar | 143 |
| Chinese calendar | 3417/3477-12-2 (庚申年十二月初二日) — to —
3418/3478-12-12(辛酉年十二月十二日) |
| Coptic calendar | 497 – 498 |
| Ethiopian calendar | 773 – 774 |
| Hebrew calendar | 4541 – 4542 |
| Hindu calendars | |
| - Vikram Samvat | 836 – 837 |
| - Shaka Samvat | 703 – 704 |
| - Kali Yuga | 3882 – 3883 |
| Holocene calendar | 10781 |
| Iranian calendar | 159 – 160 |
| Islamic calendar | 164 – 165 |
| Japanese calendar | |
| Korean calendar | 3114 |
| Thai solar calendar | 1324 |