1654 (MDCLIV) was a common year starting on Thursday of the Gregorian calendar and a common year starting on Sunday of the Julian calendar, the 1654th year of the Common Era (CE) and Anno Domini (AD) designations, the 654th year of the 2nd millennium, the 54th year of the 17th century, and the 5th year of the 1650s decade. As of the start of 1654, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.