Is an Anniversary Every Month, or Every Year? The Honest Answer
Someone in the relationship says "happy anniversary" on the 14th of every month. Someone else - a sibling, a colleague, a person on the internet with strong opinions - points out that an anniversary is a yearly thing and that saying it monthly is wrong.
They are both sort of right, which is why the argument never resolves. Here is what the word actually means, why the monthly version caught on anyway, and a way to settle it that does not involve anybody being told they are celebrating incorrectly.
What the word literally means
Anniversary comes from Latin: annus, meaning year, and versus, from vertere, to turn. An anniversary is literally a turning of the year - the day a date comes back around after a full orbit.
So by the strict reading, no: an anniversary is not every month. It is every year, and the yearly part is baked into the word rather than being a convention someone invented later. This is why a wedding anniversary, a work anniversary and a death anniversary are all annual without anyone needing to specify it.
That is the case for the pedants, and it is a genuinely good case. It just is not the whole story.
Why people started saying it monthly anyway
Language does not care very much about etymology. Words drift towards whatever people need them to do.
And early on in a relationship, people need something. The first year is the stretch where the relationship is least certain and most exciting, and a whole year is an absurdly long time to wait before you are allowed to acknowledge it. Twelve months in, you are a different pair of people than you were at week three. Waiting for one annual milestone to mark all of that is like being allowed one photograph a year.
So couples borrowed the nearest available word. Not because they thought a month was a year, but because English did not offer them anything better and "it has been four months" is not something you can put on a cake.
The words that exist for the monthly version
There are three in circulation, and they are not equally respectable.
- •Monthsary - by far the most used, especially in India, the Philippines and across South and Southeast Asia. It is a blend of month and anniversary. No dictionary has adopted it, and everyone under thirty knows exactly what it means.
- •Monthiversary - the same idea with a more obvious seam. Slightly more common in American usage. Sounds a bit more like a joke about itself, which some people prefer.
- •Mensiversary - the etymologically tidy one, from Latin mensis for month. It is correct in the way a very correct thing can be, and almost nobody says it out loud.
So is saying "happy anniversary" monthly actually wrong?
It is imprecise rather than wrong, and the distinction matters.
In practice nobody is confused. If your partner messages "happy anniversary" on a random Tuesday in month seven, you do not spend a moment wondering whether you have somehow been together for seven years. Context does all the work, and language that communicates successfully is doing its job.
Where it genuinely does cause trouble is anywhere the distinction carries weight. Telling a colleague you are celebrating your anniversary when you mean month five will get you a slightly confused reaction. Putting it on a card from a relative is a similar mismatch. In those settings the yearly meaning is the one people load by default.
The workable rule: monthly among yourselves, yearly in public. That is not a compromise so much as an accurate description of what most couples already do.
The dates that actually reward celebrating
The more interesting question is not what to call it, but which ones to bother with. Marking every single month has a way of collapsing into an obligation - a reminder that fires, a hurried dinner, a slight guilt when one of you forgets.
Couples who keep this fun tend to keep the monthly ones small and save the effort for a handful of dates that genuinely feel different.
- •Month one - the only monthsary that still feels novel. Worth doing properly once.
- •Month six - the halfway mark, and the point where most couples have stopped auditioning and started planning.
- •The first year - the real anniversary, in the strict sense and in the way it feels.
- •Day 100 and day 1000 - day counts rather than month counts, which is precisely why they land differently. They arrive on ordinary days with no obligation attached.
- •Anything private - the day you first met rather than the day you started dating, the anniversary of a trip, the date of some small thing only the two of you would count.
Why day counts sidestep the argument entirely
There is a reason day counting has quietly become more popular than the monthsary-versus-anniversary debate it replaced.
Months are genuinely ambiguous. If you started on the 31st, you have no monthsary in February, April, June, September or November, and couples argue about whether it moves to the 30th, the 28th, or the 1st of the next month. Anyone who started dating near the end of a month has run into this.
Days have none of that. A day is a day in every month and every year, leap years included. Day 100 is unambiguously day 100. Nobody has to make a ruling, and nothing gets skipped because of how many days February has.
If you want the number without doing the arithmetic, our how many days have we been together calculator will give you your count and the dates of the milestones ahead.
The short version
An anniversary, strictly, is yearly - the word means a turning of the year, and there is no version of the etymology where it means a month.
In everyday use between two people, saying it monthly is harmless and universally understood. If you want a word that is both precise and normal, monthsary is the one that has actually caught on. If you want to avoid the debate altogether, count days instead.
What none of this settles is the far more practical question of which date your monthsary falls on when the month is short - and that one genuinely does need answering. We have worked through it in our guides on the best date to celebrate a monthsary, and on what to do when you started dating on the 31st.