831
| Years | 
|---|
| Millennium | 
| 1st millennium | 
| Centuries | 
| Decades | 
| Years | 
| 831 by topic | 
|---|
| Leaders | 
| Categories | 
| 
 | 
| Gregorian calendar | 831 DCCCXXXI | 
| Ab urbe condita | 1584 | 
| Armenian calendar | 280 ԹՎ ՄՁ | 
| Assyrian calendar | 5581 | 
| Balinese saka calendar | 752–753 | 
| Bengali calendar | 237–238 | 
| Berber calendar | 1781 | 
| Buddhist calendar | 1375 | 
| Burmese calendar | 193 | 
| Byzantine calendar | 6339–6340 | 
| Chinese calendar | 庚戌年 (Metal Dog) 3528 or 3321 — to — 辛亥年 (Metal Pig) 3529 or 3322 | 
| Coptic calendar | 547–548 | 
| Discordian calendar | 1997 | 
| Ethiopian calendar | 823–824 | 
| Hebrew calendar | 4591–4592 | 
| Hindu calendars | |
| - Vikram Samvat | 887–888 | 
| - Shaka Samvat | 752–753 | 
| - Kali Yuga | 3931–3932 | 
| Holocene calendar | 10831 | 
| Iranian calendar | 209–210 | 
| Islamic calendar | 215–216 | 
| Japanese calendar | Tenchō 8 (天長8年) | 
| Javanese calendar | 727–728 | 
| Julian calendar | 831 DCCCXXXI | 
| Korean calendar | 3164 | 
| Minguo calendar | 1081 before ROC 民前1081年 | 
| Nanakshahi calendar | −637 | 
| Seleucid era | 1142/1143 AG | 
| Thai solar calendar | 1373–1374 | 
| Tibetan calendar | 阳金狗年 (male Iron-Dog) 957 or 576 or −196 — to — 阴金猪年 (female Iron-Pig) 958 or 577 or −195 | 
Year 831 (DCCCXXXI) was a common year starting on Sunday of the Julian calendar.