| Millennium: | 1st millennium |
|---|---|
| Centuries: | 8th century – 9th century – 10th century |
| Decades: | 790s 800s 810s – 820s – 830s 840s 850s |
| Years: | 825 826 827 – 828 – 829 830 831 |
| 828 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 828 DCCCXXVIII |
| Ab urbe condita | 1581 |
| Armenian calendar | 277 ԹՎ ՄՀԷ |
| Bahá'í calendar | -1016 – -1015 |
| Bengali calendar | 235 |
| Berber calendar | 1778 |
| Buddhist calendar | 1372 |
| Burmese calendar | 190 |
| Byzantine calendar | 6336 – 6337 |
| Chinese calendar | 丁未年十二月十一日 (3464/3524-12-11) — to —
戊申年十一月廿一日(3465/3525-11-21) |
| Coptic calendar | 544 – 545 |
| Ethiopian calendar | 820 – 821 |
| Hebrew calendar | 4588 – 4589 |
| Hindu calendars | |
| - Bikram Samwat | 884 – 885 |
| - Shaka Samvat | 750 – 751 |
| - Kali Yuga | 3929 – 3930 |
| Holocene calendar | 10828 |
| Iranian calendar | 206 – 207 |
| Islamic calendar | 212 – 213 |
| Japanese calendar | |
| Korean calendar | 3161 |
| Thai solar calendar | 1371 |