How it is worked out
anniversary = same date of the year in which the years fall due
Why it is done this way
An anniversary is a date that repeats, so what has to be worked out is not a difference but a position: how many whole years have passed and when the same day and month come round again. The only awkward case is 29 February, which exists one year in four and is marked on the 28th the rest of the time.
Step by step
- Count the whole years from the original date to today
- Add one more to place the next anniversary
- Give that year the same day and month as the original date
- Count the days from today to that date
What is worth knowing
The traditional names of wedding anniversaries vary by country and by list, but three of them agree almost everywhere: silver at 25, gold at 50 and diamond at 60. For the rest it is worth not trusting a table found at random, because paper, cotton and leather sit in a different order in every tradition. What does not change is the date, which is what this page works out.