BirthdayWe count our lives in years because the calendar makes it easy, but a year is just one arbitrary unit. Counting in days, hours or seconds produces milestones that arrive at unexpected moments, and many of them are far more fun to celebrate than one more ordinary birthday. The figures below are approximate, since the exact date depends on leap years and on the day you were born.
Milestones counted in days
Your 1,000th day arrives at roughly 2 years and 9 months. The 5,000th day lands at about 13 years and 8 months, right as many people become teenagers. The 10,000th day is the one most worth marking: it arrives at about 27 years and 4 and a half months, so it falls in your late twenties no matter when you were born. Later milestones include the 20,000th day at about 54 years and 9 months, and the 25,000th day at about 68 years and 5 months.
Milestones counted in hours and seconds
Your 100,000th hour arrives at about 11 years and 5 months. The big one for second-counters is one billion seconds, which equals 11,574 days and arrives at about 31 years and 8 months. It is a surprisingly good party excuse, because almost nobody notices it, and it always comes a few months before your 32nd birthday.
How to find the date of your own milestone
The simplest way is to open our Age Calculator, enter your date of birth and read the 'Total days' figure, which tells you how many days you have already lived. To find the future date of a milestone, use our Date Difference Calculator: enter your birth date as the first date, then try future dates as the second date until the total reaches the number you want. In a spreadsheet you can also type your birth date and add 10000 to get the date of your 10,000th day directly.
One small detail: do you count the day you were born?
Depending on whether you count the day you were born as day 0 or day 1, the result shifts by one day. For celebrating, that difference does not matter, so pick whichever sounds better and stick with it.
Why it is worth doing
Milestones in days and seconds make good excuses for small celebrations, such as a 10,000-day dinner, a photo on your 1,000th day, or a message to a friend whose big number is coming up. They also work for relationships: our Anniversary Calculator shows exactly how long you have been together, and 1,000 days together is about 2 years and 9 months, a milestone most couples never think to mark.