| Millennium: | 1st Millennium |
|---|---|
| Centuries: | 6th cent. – 7th cent. – 8th cent. |
| Decades: | 610s 620s 630s – 640s – 650s 660s 670s |
| Years: | 638 639 640 – 641 – 642 643 644 |
| Gregorian calendar | 641 DCXLI |
| Ab urbe condita | 1394 |
| Armenian calendar | 90 ԹՎ Ղ |
| Assyrian calendar | 5391 |
| Bengali calendar | 48 |
| Berber calendar | 1591 |
| Buddhist calendar | 1185 |
| Burmese calendar | 3 |
| Byzantine calendar | 6149–6150 |
| Chinese calendar | 庚子年 (Metal Rat) 3337 or 3277 — to — 辛丑年 (Metal Ox) 3338 or 3278 |
| Coptic calendar | 357–358 |
| Discordian calendar | 1807 |
| Ethiopian calendar | 633–634 |
| Hebrew calendar | 4401–4402 |
| Hindu calendars | |
| - Vikram Samvat | 697–698 |
| - Shaka Samvat | 562–563 |
| - Kali Yuga | 3741–3742 |
| Holocene calendar | 10641 |
| Iranian calendar | 19–20 |
| Islamic calendar | 20–21 |
| Japanese calendar | N/A |
| Javanese calendar | 531–532 |
| Julian calendar | 641 DCXLI |
| Korean calendar | 2974 |
| Minguo calendar | 1271 before ROC 民前1271年 |
| Nanakshahi calendar | −827 |
| Seleucid era | 952/953 AG |
| Thai solar calendar | 1183–1184 |
The year 641 BC