Tested tool guide
Tested browser tools
Checked August 16, 2026
What Birthday Reminder List does, with a checked example
This tool stores a list of birthdays, each with a name and date, and presents them in order of the next upcoming birthday. For each entry it shows the number of days until that birthday and the age the person will turn on that date. Unlike a simple calendar, it rolls the date forward each year, so a birthday that already passed this year appears with its countdown to next year. The most common surprise is that the age shown is the age at the next birthday, not the current age today.
Worked example
A concrete input and expected output from the current implementation.
Input
Name: Alice
Date: 2000-03-11
Name: Bob
Date: 1995-09-22
Name: Carol
Date: 1988-01-30
->
Expected output
Alice - birthday Mar 11 - 63 days until next birthday - will turn 25
Bob - birthday Sep 22 - 258 days until next birthday - will turn 30
Carol - birthday Jan 30 - 23 days until next birthday - will turn 37
Assuming today is 2025-01-07, the next birthdays in chronological order are Carol (Jan 30), Alice (Mar 11), and Bob (Sep 22). Ages are computed at the upcoming birthday.