| Centuries: | 8th century - 9th century - 10th century |
| Decades: | 810s 820s 830s - 840s - 850s 860s 870s |
| Years: | 840 841 842 - 843 - 844 845 846 |
| 843 by topic | |
| Politics | |
| State leaders - Sovereign states | |
| Birth and death categories | |
| Births - Deaths | |
| Establishment and disestablishment categories | |
| Establishments - Disestablishments | |
| Gregorian calendar | 843 DCCCXLIII |
| Ab urbe condita | 1596 |
| Armenian calendar | 292 ԹՎ ՄՂԲ |
| Bahá'í calendar | -1001 – -1000 |
| Berber calendar | 1793 |
| Buddhist calendar | 1387 |
| Burmese calendar | 205 |
| Chinese calendar | 3479/3539-11-27 (壬戌年十一月廿七日) — to — 3480/3540-12-7(癸亥年十二月初七日) |
| Coptic calendar | 559 – 560 |
| Ethiopian calendar | 835 – 836 |
| Hebrew calendar | 4603 – 4604 |
| Hindu calendars | |
| - Vikram Samvat | 898 – 899 |
| - Shaka Samvat | 765 – 766 |
| - Kali Yuga | 3944 – 3945 |
| Holocene calendar | 10843 |
| Iranian calendar | 221 – 222 |
| Islamic calendar | 228 – 229 |
| Japanese calendar | |
| Korean calendar | 3176 |
| Thai solar calendar | 1386 |