How to use the upcoming birthdays and anniversaries list
- Enter one person or event per line as a name, a comma and a date. The date can be 1990-03-15, 03-15 (no year) or 3/15/1990.
- Choose the day to count from. It starts as today and can be any date.
- Choose where a February 29 date falls in years that are not leap years: February 28 or March 1.
- Read who is next, the days away, the age being reached and a summary by month, and copy or download the list.
Formula
next date = this year's date if it is on or after the start day, otherwise next year's
days away = day number of the next date - day number of the start day
turning = year of the next date - year of the original date (blank when there is no year)
A date that matches the start day is today, 0 days away. In years without a February 29, the leap day date is moved to February 28 or March 1 as you choose.
Counting from 10 October 2026
With the sample list, Ben (1990-10-17) is next at 7 days, turning 36, followed by Eli (1975-10-20) at 10 days, Dev (2001-12-31) at 82 days, Cleo (02-29) at 141 days and Ana (1988-03-15) at 156 days, turning 39.
Cleo's date has no year and falls on a leap day. 2027 is not a leap year, so the next date is 28 February 2027, which is 141 days after 10 October 2026. With March 1 chosen it becomes 1 March 2027, 142 days away.
Things to be careful with
The year is optional, so a list can hold birthdays where only the day is known. Age is shown only when a year was given. Dates written as 3/15 follow the month first style used in the United States, so 3/4 means March 4. If your dates use the day first, write them as 1990-03-04 to be safe.
To see the exact age of one person, use the Age Calculator, and for the time since a start date and the next milestones, the Anniversary Calculator. To print a calendar to mark the dates on, use the Printable Calendar Maker.
Privacy
Names and dates stay in your browser. They are not stored or sent anywhere, and the page does not keep them in the link you share.
Assumptions and limits
- Dates use the Gregorian calendar and the day must exist in its month; 29 February needs a leap year when a year is given.
- A line with a comma in the name is read by splitting at the last comma, so the date is whatever follows it.
- Up to 500 lines are accepted and ties on days away are sorted by name.
- The count-from date must be a valid date from the year 1000 on.
- The tests compare 120 people with Python datetime, including leap days and dates equal to the start day.
Frequently asked questions
What is shown when the date is today?
Today appears in the Days away column, and the age is the age being reached on that day.
Can I list anniversaries instead of birthdays?
Yes. The same rules work for any yearly date. Turning then shows the number of years, such as the anniversary being reached.
How is a leap day handled?
In years that are not leap years it is placed on February 28 or March 1, as you choose. In leap years it stays on February 29.
Why is no age shown for some people?
You gave only a month and day, so the year is unknown and an age cannot be worked out.