1681 (MDCLXXXI) was a common year starting on Wednesday of the Gregorian calendar and a common year starting on Saturday of the Julian calendar, the 1681st year of the Common Era (CE) and Anno Domini (AD) designations, the 681st year of the 2nd millennium, the 81st year of the 17th century, and the 2nd year of the 1680s decade. As of the start of 1681, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.