1788 (MDCCLXXXVIII) was a leap year starting on Tuesday of the Gregorian calendar and a leap year starting on Saturday of the Julian calendar, the 1788th year of the Common Era (CE) and Anno Domini (AD) designations, the 788th year of the 2nd millennium, the 88th year of the 18th century, and the 9th year of the 1780s decade. As of the start of 1788, the Gregorian calendar was 11 days ahead of the Julian calendar, which remained in localized use until 1923.