Calendar-accurate age from any date of birth, including the awkward cases.
Leave blank to use today.
What the age calculator does
Age looks simple until you try to write it down. Months have different lengths, leap years add a day every four years, and 'two months and a bit' depends on which two months. This calculator counts the way people and paperwork do: whole years first, then whole months, then the days left over.
You also get totals in months, weeks and days, and the exact date and weekday of the next birthday.
How to use it
- Enter the date of birth. Use the date field so the format matches your device's locale.
- Set a comparison date if you need one. Leave it blank for today, or set a future date to find out how old someone will be then.
- Read the breakdown. The first figure is the conventional age: complete years, then complete months, then remaining days.
Features
- Exact age in years, months and days
- Totals in months, weeks and days
- Next birthday date, weekday and countdown
- Age at any chosen date, not just today
- Leap years handled correctly, including 29 February birthdays
- Clear error when the dates are the wrong way round
Common uses
- Filling in a form that asks for age in years and months
- Checking eligibility for a school year, licence or pension
- Tracking a baby's age in weeks and months
- Working out how old someone will be on a future date
- Counting down to a birthday
How your data is handled
The date you enter stays in the page. It is not submitted, stored or shared, and nothing is remembered after you close the tab.
Frequently asked questions
How is age calculated here?
By counting complete years from the date of birth, then complete months, then the days left. If the day of the month has not been reached yet, the calculator borrows the length of the previous month, which is how calendars work in practice.
How are 29 February birthdays handled?
In leap years the birthday is 29 February. In other years the calculator shows 1 March, the most common convention, and says so in the result. Some jurisdictions use 28 February for legal purposes, so check local rules if it matters.
Why does the total number of months not match years times twelve plus months?
It does. The totals are derived from the same breakdown, so a person aged 3 years and 5 months is 41 total months old.
Can I calculate an age in the past?
Yes. Put an earlier date in the comparison field to find out how old someone was on that day.
Is my date of birth stored?
No. It stays in the page while the tab is open and is never sent anywhere. Nothing is saved when you close it.
Does it account for time zones?
It works with calendar dates rather than timestamps, so the result is the same wherever you are. Today's date comes from your device's clock.