| Millennium: | 1st millennium |
|---|---|
| Centuries: | |
| Decades: | |
| Years: |
| Gregorian calendar | 891 DCCCXCI |
| Ab urbe condita | 1644 |
| Armenian calendar | 340 ԹՎ ՅԽ |
| Assyrian calendar | 5641 |
| Bengali calendar | 298 |
| Berber calendar | 1841 |
| Buddhist calendar | 1435 |
| Burmese calendar | 253 |
| Byzantine calendar | 6399–6400 |
| Chinese calendar |
庚戌年 (Metal Dog) 3587 or 3527 — to — 辛亥年 (Metal Pig) 3588 or 3528 |
| Coptic calendar | 607–608 |
| Discordian calendar | 2057 |
| Ethiopian calendar | 883–884 |
| Hebrew calendar | 4651–4652 |
| Hindu calendars | |
| - Vikram Samvat | 947–948 |
| - Shaka Samvat | 812–813 |
| - Kali Yuga | 3991–3992 |
| Holocene calendar | 10891 |
| Iranian calendar | 269–270 |
| Islamic calendar | 277–278 |
| Japanese calendar |
Kanpyō 3 (寛平3年) |
| Javanese calendar | 789–790 |
| Julian calendar | 891 DCCCXCI |
| Korean calendar | 3224 |
| Minguo calendar | 1021 before ROC 民前1021年 |
| Nanakshahi calendar | −577 |
| Seleucid era | 1202/1203 AG |
| Thai solar calendar | 1433–1434 |
Year 891 (DCCCXCI) was a common year starting on Friday (link will display the full calendar) of the Julian calendar.