1844 (MDCCCXLIV) was a leap year starting on Monday of the Gregorian calendar and a leap year starting on Saturday of the Julian calendar, the 1844th year of the Common Era (CE) and Anno Domini (AD) designations, the 844th year of the 2nd millennium, the 44th year of the 19th century, and the 5th year of the 1840s decade. As of the start of 1844, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.

In the Philippines, 1844 had only 365 days instead of 366, when Tuesday, December 31 was skipped as Monday, December 30 was immediately followed by Wednesday, January 1, 1845, the next day after. The change also applied to Caroline Islands, Guam, Marianas Islands, Marshall Islands and Palau as part of the Captaincy General of the Philippines; these became the first places on Earth to redraw the International Date Line.