Calculate your exact age in years, months and days – plus days lived, weeks, hours, weekday of birth and countdown to your next birthday.
Fill in the fields below and click "Calculate".
Calculate Age and Time Spans Precisely
How old am I today – to the exact day? How many days lie between two dates? This calculator answers both: it breaks the span between start date and reference date into years, months and days and additionally converts it into total days, weeks, months and hours. Someone born on 15 March 1990 is exactly 36 years, 4 months and 8 days old on 23 July 2026 – that's 13,279 days lived, or roughly 318,700 hours.
Why month arithmetic is not trivial
Months differ in length, and leap years insert an extra day every four years. The calculator therefore uses true calendar arithmetic instead of approximations like '30.44 days per month': from 31 January to 28 February is 'just under a month', from 15 March to 15 April exactly one. That's why two people with the same day count can have a differently worded age.
Practical use cases
The day counter helps far beyond birthdays: deadlines (e.g. 14-day withdrawal periods or warranties), length of employment for references, spacing between vaccination appointments, a baby's age in weeks for the paediatrician, or simply how many days a relationship has lasted. With the optional reference date you can also calculate into the future: how old will I be at retirement? How many days until the wedding?
Weekday of birth and anniversaries
As a bonus, the calculator reveals which weekday you were born on – 15 March 1990 was a Thursday, by the way – and counts down the days to your next birthday, including the weekday of the coming anniversary. If your birthday falls on 29 February, it shifts to 1 March in common years.
