Age Calculator
Find anyone's exact age from their date of birth, on today's date or any other day: years, months and days, plus totals and the next birthday.
- Exact years, months, days
- Any date from 1800
- Leap years counted
- Never used to train AI
Age calculator
Counts whole years, then whole months, then the days left, using the real length of each month and leap years. Change the second date to find your age on any day, past or future.
How to use the age calculator
The age calculator tells you exactly how old someone is in years, months and days, on today’s date or on any other date you choose. It runs in your browser, so the dates you type are never sent anywhere.
- Enter the date of birth. Use the date picker or type the date; any year from 1800 onwards works.
- Choose the “age on” date. It starts as today. Change it to see an age on a past date (how old was I in 2010?) or a future one (how old will I be on 1 January 2030?). Use today puts today back.
- Read the result. You get the exact age, the same span as total months, weeks, days and approximate hours, the date of the next birthday with the number of days left, and the day of the week the person was born.
- Copy it with Copy result if you need to paste the age into a form or a message.
Rather type? Ask in the box under the calculator, for example “How old is someone born on 14 March 1988?”, and the answer is worked out for you.
How the age is counted
Age is counted the way people count it in everyday life and on most official forms: first the number of whole years that have passed since the birth date, then the whole months after the last birthday, then the days that are left over. The calculator uses the real length of every month (28, 29, 30 or 31 days) and the leap years in between, so it never assumes that a month is 30 days or a year is 365 days.
Worked example: someone born on 20 August 1995, on 7 November 2026. Their 31st birthday was on 20 August 2026, so they are 31 years old. From 20 August to 20 October is 2 whole months, and from 20 October to 7 November is 18 days. The age is 31 years, 2 months and 18 days.
If the date of birth is later than the “age on” date, the calculator says so instead of showing a negative age, so you can swap the dates or correct the one you mistyped.
Your age in months, weeks, days and hours
Alongside the usual years, months and days, the calculator shows the same span in other units. These are useful for babies and young children, for milestones such as “10,000 days old”, and for school or sports rules that use an age in months.
| Shown as | How it’s worked out | Typical use |
|---|---|---|
| Total months | Whole months between the two dates | Baby and toddler ages, development checks |
| Total weeks | Total days divided by 7, whole weeks | Pregnancy and newborn milestones |
| Total days | Calendar days between the two dates | Day-count milestones and celebrations |
| Hours (approx.) | Total days × 24 | Fun facts; it ignores the time of birth and clock changes |
The hours figure is labeled as approximate because a date has no time of day: someone born late in the evening is a few hours “younger” than the number suggests, and daylight saving changes add or remove an hour on some days.
Born on 29 February
Leap years add 29 February to the calendar to keep it in step with the Earth’s orbit. Under the Gregorian calendar, a year is a leap year if it can be divided by 4, except century years, which must be divisible by 400; that’s why 2000 was a leap year and 1900 was not (see leap year and the Gregorian calendar).
For people born on 29 February, the calculator counts the birthday on 1 March in years that don’t have a 29 February, and it tells you that it did. Some countries and organizations use 28 February instead for legal purposes, so if an exact legal age matters on that day, check the rule that applies to you.
Next birthday and the day you were born
The result also shows when the next birthday falls and how many days are left, and the age the person will turn. On the birthday itself it says so. It also shows the day of the week you were born on, which is a nice detail for invitations, cards and family trees, and a quick way to check that a date of birth was typed correctly: if Grandma always said she was born on a Sunday and the calculator says Thursday, one of the digits is probably wrong.
When people need an exact age
Forms and applications
Visa, passport, insurance and job forms often ask for age on a specific date. Set the “age on” date to the application or travel date instead of today.
School and sports
Admission and age-group rules use a cut-off date. Enter that date to see whether a child is old enough, and by how many months and days.
Babies and children
Pediatric milestones are often given in weeks or months. The totals show both at once.
Family history
Work out how old an ancestor was on a census date, a wedding or a move, using any year from 1800.
Milestones
Find the day you’ll be 10,000 days old, or how many weeks old you are today.
Planning
See how old you’ll be at a future date, such as a retirement, a graduation or a big trip.
Working out age by hand
If you need to check a result on paper, use the same three steps the calculator uses:
- Years: subtract the birth year from the current year. If this year’s birthday hasn’t happened yet, subtract 1.
- Months: count the whole months from the last birthday to the latest date with the same day number that isn’t after today.
- Days: count the remaining days to today.
The step people most often get wrong is the last one, when the birth day number doesn’t exist in a month (for example the 31st in a 30-day month). The calculator handles this using the real calendar, which is why its answer can differ by a day from a quick mental estimate.
Other date calculations
An age is just one kind of date difference. To count the days between any two dates, add or subtract days from a date, or count working days, use the date calculator. For health calculations that use your age, such as daily energy needs, see the calorie calculator and the BMI calculator.
Ask in plain words
In the box under the calculator, or in the AI workspace, you can ask questions such as:
- “How old will I be on 1 January 2030 if I was born on 5 May 1991?”
- “What day of the week was 12 July 1985?”
- “How many days until my 40th birthday?”
Privacy
The age calculator runs entirely in your browser. Dates of birth are not uploaded, stored or used to train AI. Read more in Trust and privacy.
Age calculator: questions and answers
How do I calculate my age from my date of birth?
Enter your date of birth in the calculator above. It shows your exact age in years, months and days on today’s date, plus the same span in months, weeks and days.
Can I find my age on a past or future date?
Yes. Change the “age on” date to any day from 1800 to 2200, for example a travel date or a cut-off date on a form.
Does the calculator count leap years?
Yes. It uses the real calendar, including 29 February in leap years and the real length of each month.
What if I was born on 29 February?
In years without 29 February, your birthday is counted on 1 March, and the result says so. Some legal systems use 28 February instead.
Why is the number of hours marked as approximate?
It’s the number of days × 24. It doesn’t know the time you were born, and it ignores clock changes for daylight saving time.
Is my date of birth saved?
No. The calculation runs in your browser and nothing is sent or stored.
How do I work out the age of a baby in weeks?
Enter the baby’s date of birth: the result shows total weeks and total months next to the age in years, months and days.