WhenMathRelationship / Event Anniversary Calculator
Enter an event date (a relationship start, a founding date, any recurring annual event). See each anniversary, plus an optional "observed date" if the actual date falls on a weekend.
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Worked example
An event date recurring annually with no observed-date rule always lands on the actual calendar date, whatever day of the week that happens to be. Turn on the nearest-weekday rule instead, and any anniversary that would otherwise fall on a Saturday shifts back one day to the preceding Friday, while one falling on a Sunday shifts forward one day to the following Monday, keeping every observed date on a weekday.
Common mistakes
- Assuming an observed-date shift happens automatically. It only applies when one of the two shift options is explicitly selected, since the default is always the actual calendar date.
- Forgetting to set a leap-day policy for an anniversary that originally fell on February 29. Without one selected, the plan cannot resolve that date in a non-leap year.
Limitations
This is a planning calculation only. It does not determine any legal status, or any status tied to a specific relationship, program, or jurisdiction.
Frequently asked questions
- What is the difference between nearest weekday and following Monday?
- Nearest weekday shifts a Saturday back to Friday and a Sunday forward to Monday, while following Monday always shifts forward to the next Monday regardless of which weekend day the anniversary actually falls on.
- Does the leap-day policy interact with the observed-date rule?
- Yes, the leap-day policy is applied first to resolve a Feb 29 anniversary to an actual calendar date, and only then does the observed-date rule check whether that resolved date happens to fall on a weekend.