How to use
Enter the day you started dating, or a baby’s birthday, as the start date. The reference date defaults to today; change it to recalculate from another day. The result shows what day count today is (with the start date counted as day 1), plus a table of the 100th, 200th, 300th, 500th and 1000th days and the 1st–3rd anniversaries, with each one’s date and how many days remain (D-day) from the reference date.
Why the start date counts as day one
In Korea, couples celebrate the day they have been together for 100, 200 or 1000 days, and a baby’s 100th day is called baekil. In both cases, the start date itself (the first day together, or the day of birth) counts as day 1. This is one day off from an ordinary day count that measures how many days have passed since the start date. For example, if you started on June 13, day 100 falls on September 20 — which is 99 days after the start date.
The milestone list
The tool shows the dates for the 100th, 200th, 300th, 500th and 1000th days and the 1st–3rd anniversaries, together with how many days remain until each one (D-day) from the reference date. Yearly anniversaries fall on the same month and day each year; if the start date is February 29, a non-leap year’s anniversary is calculated as February 28.