Back 401 Abkhazian 401 Afrikaans 401 ALS 401 እ.ኤ.አ. Amharic 401 AN 401 Arabic 401 AST 401 Azerbaijani ۴۰۱ (میلادی) AZB 401 BAN
| Millennium: | 1st millennium |
|---|---|
| Centuries: | 4th century – 5th century – 6th century |
| Decades: | 370s 380s 390s – 400s – 410s 420s 430s |
| Years: | 398 399 400 – 401 – 402 403 404 |
| Gregorian calendar | 401 CDI |
| Ab urbe condita | 1154 |
| Assyrian calendar | 5151 |
| Balinese saka calendar | 322–323 |
| Bengali calendar | −192 |
| Berber calendar | 1351 |
| Buddhist calendar | 945 |
| Burmese calendar | −237 |
| Byzantine calendar | 5909–5910 |
| Chinese calendar | 庚子年 (Metal Rat) 3097 or 3037 — to — 辛丑年 (Metal Ox) 3098 or 3038 |
| Coptic calendar | 117–118 |
| Discordian calendar | 1567 |
| Ethiopian calendar | 393–394 |
| Hebrew calendar | 4161–4162 |
| Hindu calendars | |
| - Vikram Samvat | 457–458 |
| - Shaka Samvat | 322–323 |
| - Kali Yuga | 3501–3502 |
| Holocene calendar | 10401 |
| Iranian calendar | 221 BP – 220 BP |
| Islamic calendar | 228 BH – 227 BH |
| Javanese calendar | 284–285 |
| Julian calendar | 401 CDI |
| Korean calendar | 2734 |
| Minguo calendar | 1511 before ROC 民前1511年 |
| Nanakshahi calendar | −1067 |
| Seleucid era | 712/713 AG |
| Thai solar calendar | 943–944 |
| Tibetan calendar | 阳金鼠年 (male Iron-Rat) 527 or 146 or −626 — to — 阴金牛年 (female Iron-Ox) 528 or 147 or −625 |
401 (CDI) was a common year starting on Tuesday of the Julian calendar, the 401st year of the Common Era (CE) and Anno Domini (AD) designations, the 401st year of the 1st millennium, the 1st year of the 5th century, and the 2nd year of the 400s decade. As of the start of 401, the Gregorian calendar was 1 day ahead of the Julian calendar, which was the dominant calendar of the time.