A very merry unbirthday
In Lewis Carroll’s Through the Looking-Glass, Humpty Dumpty proudly shows Alice the cravat he was given as an unbirthday present, and does the sums for her: 365 days in a year, minus one birthday, leaves 364 days on which you might get unbirthday presents. It is a joke, but it is also a rather lovely way of looking at the calendar, because it turns every ordinary day into a small occasion. The ring above shows the current year of your life as a circle of days, starting from your last birthday, with today marked and your next birthday at the top.
Almost every day you have lived has been an unbirthday, so the total is very close to your age in days. The fun is in the reframing: you have had thousands of them, and today is another.
How we calculate it
We count every day from the day after you were born up to and including today, then subtract the birthdays that fell in that time. Days in leap years are counted too, so a year with a 29 February gives you 365 unbirthdays rather than 364. If you were born on 29 February, your birthday only appears in leap years, so in other years every single day is an unbirthday.
| Age | Unbirthdays (approx.) |
|---|---|
| 1 | 364 or 365 |
| 10 | about 3,642 |
| 18 | about 6,557 |
| 30 | about 10,928 |
| 50 | about 18,213 |
Worked example. Someone born on 12 April 1990 had lived 13,350 days by 30 October 2026. They had had 36 birthdays in that time, so they had enjoyed 13,350 − 36 = 13,314 unbirthdays. Between then and their next birthday there were 163 more to go.
Celebrate a random Tuesday
The unbirthday idea is a nice nudge to mark ordinary days. A small treat, a call to a friend or an unbirthday card for someone whose real birthday is months away can feel more surprising than a birthday present, precisely because nobody expects it.
Questions people ask
What is an unbirthday?
Any day that is not your birthday. The idea comes from Lewis Carroll’s Through the Looking-Glass (1871), where Humpty Dumpty explains that there are 364 days when you might get unbirthday presents, and only one for birthday presents.
Is it from Alice in Wonderland?
The word is Carroll’s, from Through the Looking-Glass. The famous “Very Merry Unbirthday” song sung by the Mad Hatter and March Hare comes from Disney’s 1951 film Alice in Wonderland, which mixed both books.
How many unbirthdays are in a year?
364 in a common year and 365 in a leap year, unless you were born on 29 February, in which case you get 365 unbirthdays in common years.
Is today my unbirthday?
Almost certainly. The page shows a banner either way.
Sources. Lewis Carroll, Through the Looking-Glass, and What Alice Found There (1871), chapter 6. Calculations run in your browser; nothing you enter is sent anywhere.