Work out anniversary date instantly with clear inputs, formula shown and shareable results.
An anniversary is the same calendar date with the year advanced, so the fifteenth anniversary of 4 July 2015 is 4 July 2030 - a Thursday. From 4 September 2026 that is 1400 days away, with 11.2 years already elapsed. Because 365 is not divisible by seven, the weekday advances one or two places each year.
Anniversary date
date = original date with the year advanced by n
Days until
days = anniversary date - today
Because a common year is 52 weeks plus one day, so the date moves forward one weekday - two after a leap day.
They only recur every four years. Most conventions observe 28 February or 1 March in common years.