1340
| Years | 
|---|
| Millennium | 
| 2nd millennium | 
| Centuries | 
| Decades | 
| Years | 
| 1340 by topic | 
|---|
| Leaders | 
| 
 | 
| Birth and death categories | 
| Births – Deaths | 
| Establishments and disestablishments categories | 
| Establishments – Disestablishments | 
| Art and literature | 
| 1340 in poetry | 
| Gregorian calendar | 1340 MCCCXL | 
| Ab urbe condita | 2093 | 
| Armenian calendar | 789 ԹՎ ՉՁԹ | 
| Assyrian calendar | 6090 | 
| Balinese saka calendar | 1261–1262 | 
| Bengali calendar | 746–747 | 
| Berber calendar | 2290 | 
| English Regnal year | 13 Edw. 3 – 14 Edw. 3 | 
| Buddhist calendar | 1884 | 
| Burmese calendar | 702 | 
| Byzantine calendar | 6848–6849 | 
| Chinese calendar | 己卯年 (Earth Rabbit) 4037 or 3830 — to — 庚辰年 (Metal Dragon) 4038 or 3831 | 
| Coptic calendar | 1056–1057 | 
| Discordian calendar | 2506 | 
| Ethiopian calendar | 1332–1333 | 
| Hebrew calendar | 5100–5101 | 
| Hindu calendars | |
| - Vikram Samvat | 1396–1397 | 
| - Shaka Samvat | 1261–1262 | 
| - Kali Yuga | 4440–4441 | 
| Holocene calendar | 11340 | 
| Igbo calendar | 340–341 | 
| Iranian calendar | 718–719 | 
| Islamic calendar | 740–741 | 
| Japanese calendar | Ryakuō 3 (暦応3年) | 
| Javanese calendar | 1252–1253 | 
| Julian calendar | 1340 MCCCXL | 
| Korean calendar | 3673 | 
| Minguo calendar | 572 before ROC 民前572年 | 
| Nanakshahi calendar | −128 | 
| Thai solar calendar | 1882–1883 | 
| Tibetan calendar | 阴土兔年 (female Earth-Rabbit) 1466 or 1085 or 313 — to — 阳金龙年 (male Iron-Dragon) 1467 or 1086 or 314 | 
Year 1340 (MCCCXL) was a leap year starting on Saturday of the Julian calendar.