How it works
How the age calculator works out your exact age
By Toheed MehmoodReviewed How we check facts
In short
Your age is the number of birthdays you have completed, plus the whole months since your last birthday, plus the days left over. Someone born on 27 August 1992 is 34 years, 1 month and 10 days old on 7 October 2026: 34 birthdays, one full month to 27 September, then 10 more days.
- Days in a common year
- 365
- Days in a leap year
- 366
- Average Gregorian year
- 365.2425 days
- Leap years every
- 4 years, except most century years
How to calculate your age
- Pick your date of birth. The calculator starts with today as the date to measure to.
- Change Age on if you want your age on another day, for example a future exam date or a past event.
- Read your age in years, months and days, then the totals: months, weeks, days and hours lived.
Everything is worked out in your browser. The dates you enter are not sent to us or stored anywhere.
How age is counted in years, months and days
Age is counted in completed units, never rounded up. You turn a year older on your birthday, a month passes when the day of the month comes round again, and whatever is left is days.
| Step | From | To | Result |
|---|---|---|---|
| Whole years | 27 Aug 1992 | 27 Aug 2026 | 34 years |
| Whole months | 27 Aug 2026 | 27 Sep 2026 | 1 month |
| Days left | 27 Sep 2026 | 7 Oct 2026 | 10 days |
When the day of the month you were born on does not exist in a month (the 31st, or 29 February), the month ends on its last day instead. That is why someone born on 31 January is exactly 1 month old on 28 February in a common year.
How many days old am I?
Total days are counted directly between the two dates, so leap days are included automatically. Weeks are those days divided by seven, and hours are days × 24. The calculator does not use 365 days for every year, which is why its totals stay exact over long spans.
Your 10,000th day comes about 27 years and 4 months after you were born, and your 1,000th week about 19 years and 2 months after.
How old are you if you were born on 29 February?
In common years there is no 29 February, so people born on a leap day usually celebrate on 28 February or 1 March. This calculator counts your new year of age from 1 March in common years, a widely used convention. Legal rules differ between countries, so check local law if the date matters for a document.
When an exact age matters
- Forms and applications that ask for age on a specific date, such as school entry, sports age groups or job applications.
- Checking eligibility for an age limit on a deadline day rather than today.
- Working out how old someone was when a photo was taken or an event happened.
- Planning milestone birthdays and anniversaries; the Birthday Countdown shows how long is left.
Need the reverse? The Date of Birth Calculator works out a birth year from an age, and What Generation Am I? tells you which generation that birth year belongs to.
Common questions
How do I calculate my age from my date of birth?
Count the birthdays you have had, then the whole months since the last one, then the remaining days. Or enter your date of birth above and the calculator does it for you, including leap years.
How old am I in days?
Enter your date of birth and the result shows the exact number of days you have lived, counted between the two dates with every leap day included.
Does the age calculator count leap years?
Yes. Totals are counted day by day on the Gregorian calendar, so every 29 February in your lifetime is included.
Can I calculate age on a future or past date?
Yes. Change the Age on date to any day after the date of birth to see the age on that day.
Is my date of birth saved?
No. The calculation runs in your browser and nothing you enter is sent to our server.
How many months old am I?
Multiply your full years by 12 and add the full months since your last birthday. The calculator also shows your total months, weeks, days and hours lived.
Sources
- Gregorian calendar · Encyclopaedia Britannica
- What is a leap year? · Royal Museums Greenwich