1240
| Years | 
|---|
| Millennium | 
| 2nd millennium | 
| Centuries | 
| Decades | 
| Years | 
| 1240 by topic | 
|---|
| Leaders | 
| 
 | 
| Birth and death categories | 
| Births – Deaths | 
| Establishments and disestablishments categories | 
| Establishments – Disestablishments | 
| Art and literature | 
| 1240 in poetry | 
| Gregorian calendar | 1240 MCCXL | 
| Ab urbe condita | 1993 | 
| Armenian calendar | 689 ԹՎ ՈՁԹ | 
| Assyrian calendar | 5990 | 
| Balinese saka calendar | 1161–1162 | 
| Bengali calendar | 646–647 | 
| Berber calendar | 2190 | 
| English Regnal year | 24 Hen. 3 – 25 Hen. 3 | 
| Buddhist calendar | 1784 | 
| Burmese calendar | 602 | 
| Byzantine calendar | 6748–6749 | 
| Chinese calendar | 己亥年 (Earth Pig) 3937 or 3730 — to — 庚子年 (Metal Rat) 3938 or 3731 | 
| Coptic calendar | 956–957 | 
| Discordian calendar | 2406 | 
| Ethiopian calendar | 1232–1233 | 
| Hebrew calendar | 5000–5001 | 
| Hindu calendars | |
| - Vikram Samvat | 1296–1297 | 
| - Shaka Samvat | 1161–1162 | 
| - Kali Yuga | 4340–4341 | 
| Holocene calendar | 11240 | 
| Igbo calendar | 240–241 | 
| Iranian calendar | 618–619 | 
| Islamic calendar | 637–638 | 
| Japanese calendar | En'ō 2 / Ninji 1 (仁治元年) | 
| Javanese calendar | 1149–1150 | 
| Julian calendar | 1240 MCCXL | 
| Korean calendar | 3573 | 
| Minguo calendar | 672 before ROC 民前672年 | 
| Nanakshahi calendar | −228 | 
| Thai solar calendar | 1782–1783 | 
| Tibetan calendar | 阴土猪年 (female Earth-Pig) 1366 or 985 or 213 — to — 阳金鼠年 (male Iron-Rat) 1367 or 986 or 214 | 
Year 1240 (MCCXL) was a leap year starting on Sunday of the Julian calendar.