| Millennium: | 1st millennium |
|---|---|
| Centuries: | |
| Decades: | |
| Years: |
| Gregorian calendar | 900 CM |
| Ab urbe condita | 1653 |
| Armenian calendar | 349 ԹՎ ՅԽԹ |
| Assyrian calendar | 5650 |
| Bengali calendar | 307 |
| Berber calendar | 1850 |
| Buddhist calendar | 1444 |
| Burmese calendar | 262 |
| Byzantine calendar | 6408–6409 |
| Chinese calendar |
己未年 (Earth Goat) 3596 or 3536 — to — 庚申年 (Metal Monkey) 3597 or 3537 |
| Coptic calendar | 616–617 |
| Discordian calendar | 2066 |
| Ethiopian calendar | 892–893 |
| Hebrew calendar | 4660–4661 |
| Hindu calendars | |
| - Vikram Samvat | 956–957 |
| - Shaka Samvat | 821–822 |
| - Kali Yuga | 4000–4001 |
| Holocene calendar | 10900 |
| Iranian calendar | 278–279 |
| Islamic calendar | 286–288 |
| Japanese calendar |
Shōtai 3 (昌泰3年) |
| Javanese calendar | 798–799 |
| Julian calendar | 900 CM |
| Korean calendar | 3233 |
| Minguo calendar | 1012 before ROC 民前1012年 |
| Nanakshahi calendar | −568 |
| Seleucid era | 1211/1212 AG |
| Thai solar calendar | 1442–1443 |
Year 900 (CM) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar.