How many days old am I?
By Matthew Parrott, who makes Life Tally ·
Type your birthday to see your age in days, counted exactly from the day you were born, with every leap day, and in weeks, months, hours, minutes and seconds too.
Free to download · iPhone and iPad
How your age in days is counted
Start on the day you were born, day 0, and count every calendar date to today. Leap days count like any other day, which is why your age in years times 365 always comes out short. A day is a date on the calendar, not a stretch of 24 hours, so a day when the clocks change still counts as one.
That's the same count Life Tally keeps on its Today screen, where you can switch between years, months, weeks, days, hours, minutes and seconds, or watch all seven at once.
How many days old you are on each birthday
Each birthday lands on one of two day counts, depending on how many February 29ths came before it. These hold for every birthday from 1900 to 2029.
| Birthday | Days old |
|---|---|
| 1st | 365 or 366 |
| 5th | 1,826 or 1,827 |
| 10th | 3,652 or 3,653 |
| 13th | 4,748 or 4,749 |
| 16th | 5,843 or 5,844 |
| 18th | 6,574 or 6,575 |
| 21th | 7,670 or 7,671 |
| 25th | 9,131 or 9,132 |
| 30th | 10,957 or 10,958 |
| 40th | 14,609 or 14,610 |
| 50th | 18,262 or 18,263 |
| 60th | 21,914 or 21,915 |
| 70th | 25,567 or 25,568 |
| 80th | 29,219 or 29,220 |
The days worth knowing about
A count of days is a number most people never look at, and some of its values are worth a look: your 10,000th day, the day your count reads 11,111, your billionth second. Life Tally finds them for you and everyone you add, dates every one, and shows the arithmetic behind it. Most days are quiet, and the app says so.
Checked against Life Tally 4.0 on October 27, 2026.
Questions
How do I work out how many days old I am?
Count the calendar days from your birthday to today: the day you were born is day 0, so on your first birthday you are 365 days old, or 366 if a February 29 came in between. Multiplying your age in years by 365 misses the leap days, about one every four years, so a 30-year-old would come out 7 or 8 days short.
How many days old is a 30-year-old?
On your 30th birthday you are 10,957 or 10,958 days old, depending on how many February 29ths your first 30 years held. On your 18th birthday it's 6,574 or 6,575.
Does the day I was born count as a day?
It's day 0. Your count turns to 1 at your first midnight, the way your age in years turns to 1 on your first birthday. Life Tally counts the same way, so the day it calls your 10,000th day is the day you are 10,000 days old.
How many seconds old am I?
Without a birth time, the count starts at midnight on the day you were born; the calculator above shows that number, still counting. If you know the minute you were born, add it in Life Tally and the hours, minutes and seconds count from that minute instead.
When is my 10,000th day?
Your birthday plus 10,000 days, when you are 27 years, 4 months and 15 to 19 days old. The 10,000th day page works it out for any birthday.