| Millennium: | 1st millennium BC |
|---|---|
| Centuries: | |
| Decades: | |
| Years: |
| 28 BC by topic |
| Politics |
|---|
| Categories |
| Gregorian calendar | 28 BC XXVIII BC |
| Ab urbe condita | 726 |
| Ancient Greek era | 188th Olympiad (victor)¹ |
| Assyrian calendar | 4723 |
| Balinese saka calendar | N/A |
| Bengali calendar | −620 |
| Berber calendar | 923 |
| Buddhist calendar | 517 |
| Burmese calendar | −665 |
| Byzantine calendar | 5481–5482 |
| Chinese calendar | 壬辰年 (Water Dragon) 2670 or 2463 — to — 癸巳年 (Water Snake) 2671 or 2464 |
| Coptic calendar | −311 – −310 |
| Discordian calendar | 1139 |
| Ethiopian calendar | −35 – −34 |
| Hebrew calendar | 3733–3734 |
| Hindu calendars | |
| - Vikram Samvat | 29–30 |
| - Shaka Samvat | N/A |
| - Kali Yuga | 3073–3074 |
| Holocene calendar | 9973 |
| Iranian calendar | 649 BP – 648 BP |
| Islamic calendar | 669 BH – 668 BH |
| Javanese calendar | N/A |
| Julian calendar | 28 BC XXVIII BC |
| Korean calendar | 2306 |
| Minguo calendar | 1939 before ROC 民前1939年 |
| Nanakshahi calendar | −1495 |
| Seleucid era | 284/285 AG |
| Thai solar calendar | 515–516 |
| Tibetan calendar | 阳水龙年 (male Water-Dragon) 99 or −282 or −1054 — to — 阴水蛇年 (female Water-Snake) 100 or −281 or −1053 |
Year 28 BC was either a common year starting on Saturday, Sunday or Monday or a leap year starting on Saturday or Sunday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a common year starting on Saturday of the Proleptic Julian calendar. At the time, it was known as the Year of the First Consulship of Octavian and Agrippa (or, less frequently, year 726 Ab urbe condita). The denomination 28 BC 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.