| Millennium: | 1st Millennium BC |
|---|---|
| Centuries: | 2nd cent. BC – 1st cent. BC – 1st cent. |
| Decades: | 40s BC 30s BC 20s BC – 10s BC – 0s BC 0s 10s |
| Years: | 21 BC 20 BC 19 BC – 18 BC – 17 BC 16 BC 15 BC |
| Gregorian calendar | 18 XVIII |
| Ab urbe condita | 771 |
| Assyrian calendar | 4768 |
| Bengali calendar | −575 |
| Berber calendar | 968 |
| Buddhist calendar | 562 |
| Burmese calendar | −620 |
| Byzantine calendar | 5526–5527 |
| Chinese calendar | 丁丑年 (Fire Ox) 2714 or 2654 — to — 戊寅年 (Earth Tiger) 2715 or 2655 |
| Coptic calendar | −266 – −265 |
| Discordian calendar | 1184 |
| Ethiopian calendar | 10–11 |
| Hebrew calendar | 3778–3779 |
| Hindu calendars | |
| - Vikram Samvat | 74–75 |
| - Shaka Samvat | N/A |
| - Kali Yuga | 3118–3119 |
| Holocene calendar | 10018 |
| Iranian calendar | 604 BP – 603 BP |
| Islamic calendar | 623 BH – 622 BH |
| Javanese calendar | N/A |
| Julian calendar | 18 XVIII |
| Korean calendar | 2351 |
| Minguo calendar | 1894 before ROC 民前1894年 |
| Nanakshahi calendar | −1450 |
| Seleucid era | 329/330 AG |
| Thai solar calendar | 560–561 |
The year 18 BC