251
| Millennium: | 1st millennium |
|---|---|
| Centuries: | 2nd century – 3rd century – 4th century |
| Decades: | 220s 230s 240s – 250s – 260s 270s 280s |
| Years: | 248 249 250 – 251 – 252 253 254 |
| Gregorian calendar | 251 CCLI |
| Ab urbe condita | 1004 |
| Assyrian calendar | 5001 |
| Balinese saka calendar | 172–173 |
| Bengali calendar | −342 |
| Berber calendar | 1201 |
| Buddhist calendar | 795 |
| Burmese calendar | −387 |
| Byzantine calendar | 5759–5760 |
| Chinese calendar | 庚午年 (Metal Horse) 2947 or 2887 — to — 辛未年 (Metal Goat) 2948 or 2888 |
| Coptic calendar | −33 – −32 |
| Discordian calendar | 1417 |
| Ethiopian calendar | 243–244 |
| Hebrew calendar | 4011–4012 |
| Hindu calendars | |
| - Vikram Samvat | 307–308 |
| - Shaka Samvat | 172–173 |
| - Kali Yuga | 3351–3352 |
| Holocene calendar | 10251 |
| Iranian calendar | 371 BP – 370 BP |
| Islamic calendar | 382 BH – 381 BH |
| Javanese calendar | 129–130 |
| Julian calendar | 251 CCLI |
| Korean calendar | 2584 |
| Minguo calendar | 1661 before ROC 民前1661年 |
| Nanakshahi calendar | −1217 |
| Seleucid era | 562/563 AG |
| Thai solar calendar | 793–794 |
| Tibetan calendar | 阳金马年 (male Iron-Horse) 377 or −4 or −776 — to — 阴金羊年 (female Iron-Goat) 378 or −3 or −775 |
251 (CCLI) was a common year starting on Wednesday of the Julian calendar, the 251st year of the Common Era (CE) and Anno Domini (AD) designations, the 251st year of the 1st millennium, the 51st year of the 3rd century, and the 2nd year of the 250s decade.