How age is calculated
Full age is counted by completed birthdays. Total days uses the date difference between the birthday and today.
Age Calculator
Enter a date of birth to calculate age in full years and total days lived.
Keep exploring this topic
Use the related tools and guides when the first answer raises the next question.
How to use the age result
Use the full-years result for ordinary age checks, then use the total days or weeks when you want a milestone number for birthdays, anniversaries or records. Calendar age counts completed birthdays; total lived time counts the full gap between the date of birth and today.
Example
Someone born on 1 January 1990 is 36 years old on 15 May 2026, but the more detailed rows show the lived time in days, weeks, hours and seconds. Those smaller units are useful for milestone posts and birthday countdowns.
Common mistake
Do not estimate age by subtracting the birth year only. The month and day matter because a birthday may not have happened yet this year.