| Millennium: | 1st millennium |
|---|---|
| Centuries: | |
| Decades: | |
| Years: |
 | This article needs additional citations for verification. (February 2024) |
| 403 by topic |
|---|
| Leaders |
| Categories |
| Gregorian calendar | 403 CDIII |
| Ab urbe condita | 1156 |
| Assyrian calendar | 5153 |
| Balinese saka calendar | 324–325 |
| Bengali calendar | −190 |
| Berber calendar | 1353 |
| Buddhist calendar | 947 |
| Burmese calendar | −235 |
| Byzantine calendar | 5911–5912 |
| Chinese calendar | 壬寅年 (Water Tiger) 3100 or 2893 — to — 癸卯年 (Water Rabbit) 3101 or 2894 |
| Coptic calendar | 119–120 |
| Discordian calendar | 1569 |
| Ethiopian calendar | 395–396 |
| Hebrew calendar | 4163–4164 |
| Hindu calendars | |
| - Vikram Samvat | 459–460 |
| - Shaka Samvat | 324–325 |
| - Kali Yuga | 3503–3504 |
| Holocene calendar | 10403 |
| Iranian calendar | 219 BP – 218 BP |
| Islamic calendar | 226 BH – 225 BH |
| Javanese calendar | 286–287 |
| Julian calendar | 403 CDIII |
| Korean calendar | 2736 |
| Minguo calendar | 1509 before ROC 民前1509年 |
| Nanakshahi calendar | −1065 |
| Seleucid era | 714/715 AG |
| Thai solar calendar | 945–946 |
| Tibetan calendar | 阳水虎年 (male Water-Tiger) 529 or 148 or −624 — to — 阴水兔年 (female Water-Rabbit) 530 or 149 or −623 |
Year 403 (CDIII) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Theodosius and Rumoridus (or, less frequently, year 1156 Ab urbe condita). The denomination 403 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.