| Millennium: | 2nd Millennium BC |
|---|---|
| Centuries: | 20th cent. BC – 19th cent. BC – 18th cent. BC |
| Decades: | 1830s BC 1820s BC 1810s BC – 1800s BC – 1790s BC 1780s BC 1770s BC |
| Years: | 1804 BC 1803 BC 1802 BC – 1801 BC – 1800 BC 1799 BC 1798 BC |
| Gregorian calendar | 1801 MDCCCI |
| French Republican calendar | 9–10 |
| Ab urbe condita | 2554 |
| Armenian calendar | 1250 ԹՎ ՌՄԾ |
| Assyrian calendar | 6551 |
| Bengali calendar | 1208 |
| Berber calendar | 2751 |
| British Regnal year | 41 Geo. 3 – 42 Geo. 3 |
| Buddhist calendar | 2345 |
| Burmese calendar | 1163 |
| Byzantine calendar | 7309–7310 |
| Chinese calendar | 庚申年 (Metal Monkey) 4497 or 4437 — to — 辛酉年 (Metal Rooster) 4498 or 4438 |
| Coptic calendar | 1517–1518 |
| Discordian calendar | 2967 |
| Ethiopian calendar | 1793–1794 |
| Hebrew calendar | 5561–5562 |
| Hindu calendars | |
| - Vikram Samvat | 1857–1858 |
| - Shaka Samvat | 1722–1723 |
| - Kali Yuga | 4901–4902 |
| Holocene calendar | 11801 |
| Igbo calendar | 801–802 |
| Iranian calendar | 1179–1180 |
| Islamic calendar | 1215–1216 |
| Japanese calendar | Kansei 13 (寛政１３年) |
| Javanese calendar | 1727–1728 |
| Julian calendar | Gregorian minus 12 days |
| Korean calendar | 4134 |
| Minguo calendar | 111 before ROC 民前111年 |
| Nanakshahi calendar | 333 |
| Thai solar calendar | 2343–2344 |
The year 1801 BC