Age Calculator
The age calculator computes your exact age from your date of birth, in years, months, weeks, and days, as of today or any target date. Also shows how many days remain until your next birthday. Free, no account needed.
How to use Age Calculator
- Enter your date of birth using the date input field.
- The calculator instantly shows your exact age in years, months, weeks, and days.
- See the total number of days you have lived.
- Check the countdown to your next birthday in days.
- Enter any other date of birth to calculate someone else's age.
How old am I today: exact age from date of birth
The how old am I today calculation seems simple but involves several edge cases. The age calculator counts complete years first: a full year is credited on the anniversary of the birth date, not before. Partial months and days are then counted as the remainder. For example, someone born on 15 March 2000 who is calculating their age on 10 April 2026 has a complete age of 26 years, 0 months, and 26 days, because their 26th birthday (March 15, 2026) has passed but their next birthday (April 10 milestone) is not yet the anniversary month.
The age from date of birth calculation is exact because this calculator accounts for the actual number of days in each month and correctly handles years of varying lengths. The result is displayed in years, months, weeks, and total days, multiple representations that are useful for different purposes. Total days from birth is useful for scientific contexts. Years and months is the standard social convention. Days until next birthday is useful for planning and milestone purposes. The age calculator in years months days format is the most complete representation.
Calculate my exact age: leap years and birthday edge cases
The most complex case in age calculation is the leap year birthday, when someone is born on February 29. The age calculator handles this correctly: in non-leap years, people born on February 29 reach their birthday anniversary on March 1 (the day after February 28, the last day of February in a common year). In leap years, they celebrate on February 29 itself. The birthday countdown calculator uses the same logic: if today is February 28 in a non-leap year and your birthday is February 29, the calculator correctly shows 1 day to your next birthday (which will be March 1 this year).
The days until my birthday counter uses today's date, determined from your device's clock, as the reference point. The calculation finds the next occurrence of your birth month and birth day (or the adjusted date for February 29 birthdays) and subtracts today's date. A result of 0 means today is your birthday. The calculator updates automatically based on the current date, no need to refresh around midnight. For calculating someone else's age, enter their date of birth instead of yours.
Frequently asked questions
The calculator subtracts your date of birth from the current date (or a custom target date) using calendar arithmetic. It counts complete calendar years first, crediting a full year on each anniversary of your birth date, then counts the remaining complete months and days. The result accounts for the actual number of days in each calendar month and correctly handles leap years, producing an exact age rather than an approximation.
Yes. For people born on February 29 (leap day), the calculator treats March 1 as the birthday in non-leap years. This follows the most common legal convention used in jurisdictions that define the birthday of a February 29 person as March 1 in common years. In leap years, February 29 is recognized as the actual birthday. The days-until-birthday counter applies the same logic when computing how many days remain until the next birthday.
Yes. Simply enter the other person's date of birth into the date of birth field. The calculator accepts any valid past date and computes the exact age from that date to today (or to a custom target date). You can use this to calculate the exact age of a child, check the age of an elderly relative, compute someone's age at a specific historical or future date, or verify age eligibility.
The birthday countdown appears below your age result. The calculator finds the next occurrence of your birth month and day on or after today and counts the days between today and that date. A result of zero means today is your birthday. A result of 365 (or 366 in a leap year) means your birthday was yesterday and your next birthday is a full year away. The countdown refreshes based on today's date automatically.