1421
| Years | 
|---|
| Millennium | 
| 2nd millennium | 
| Centuries | 
| Decades | 
| Years | 
| 1421 by topic | 
|---|
| Arts and science | 
| Leaders | 
| 
 | 
| Birth and death categories | 
| Births – Deaths | 
| Establishments and disestablishments categories | 
| Establishments – Disestablishments | 
| Art and literature | 
| 1421 in poetry | 
| Gregorian calendar | 1421 MCDXXI | 
| Ab urbe condita | 2174 | 
| Armenian calendar | 870 ԹՎ ՊՀ | 
| Assyrian calendar | 6171 | 
| Balinese saka calendar | 1342–1343 | 
| Bengali calendar | 827–828 | 
| Berber calendar | 2371 | 
| English Regnal year | 8 Hen. 5 – 9 Hen. 5 | 
| Buddhist calendar | 1965 | 
| Burmese calendar | 783 | 
| Byzantine calendar | 6929–6930 | 
| Chinese calendar | 庚子年 (Metal Rat) 4118 or 3911 — to — 辛丑年 (Metal Ox) 4119 or 3912 | 
| Coptic calendar | 1137–1138 | 
| Discordian calendar | 2587 | 
| Ethiopian calendar | 1413–1414 | 
| Hebrew calendar | 5181–5182 | 
| Hindu calendars | |
| - Vikram Samvat | 1477–1478 | 
| - Shaka Samvat | 1342–1343 | 
| - Kali Yuga | 4521–4522 | 
| Holocene calendar | 11421 | 
| Igbo calendar | 421–422 | 
| Iranian calendar | 799–800 | 
| Islamic calendar | 823–824 | 
| Japanese calendar | Ōei 28 (応永28年) | 
| Javanese calendar | 1335–1336 | 
| Julian calendar | 1421 MCDXXI | 
| Korean calendar | 3754 | 
| Minguo calendar | 491 before ROC 民前491年 | 
| Nanakshahi calendar | −47 | 
| Thai solar calendar | 1963–1964 | 
| Tibetan calendar | 阳金鼠年 (male Iron-Rat) 1547 or 1166 or 394 — to — 阴金牛年 (female Iron-Ox) 1548 or 1167 or 395 | 
Year 1421 (MCDXXI) was a common year starting on Wednesday of the Julian calendar.