1650 (MDCL) was a common year starting on Saturday of the Gregorian calendar and a common year starting on Tuesday of the Julian calendar, the 1650th year of the Common Era (CE) and Anno Domini (AD) designations, the 650th year of the 2nd millennium, the 50th year of the 17th century, and the 1st year of the 1650s decade. As of the start of 1650, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.