Your exact age is the number of full years since your birth date, plus the months and days since your last birthday. Enter a date of birth below to see your age in years, months and days, your age in total months, weeks and days, and how long it is until your next birthday.
Age calculator
The calculator runs in your browser. The dates you enter are not stored or sent anywhere.
How age is calculated
- Count the full years between the date of birth and today. A year only counts once the birthday has passed.
- Count the full months since the last birthday.
- Count the remaining days since the last full month.
Worked example
Someone born on 14 March 1995 checks their age on 4 November 2026:
- Their last birthday was 14 March 2026, when they turned 31.
- From 14 March to 14 October 2026 is 7 months.
- From 14 October to 4 November 2026 is 21 days.
So they are 31 years, 7 months and 21 days old. In other units, that is 379 months and 21 days, 1,651 weeks and 1 day, or 11,558 days in total.
Age in months for babies and toddlers
Young children’s ages are usually given in months until about age 2 or 3. A baby born on 18 May 2025 is 17 months old on 4 November 2026 (1 year, 5 months and 17 days). To switch between months and years, use the months to years converter.
| Age in months | Age in years |
|---|---|
| 6 months | half a year, the halfway to one milestone |
| 12 months | 1 year |
| 18 months | 1½ years |
| 24 months | 2 years |
| 30 months | 2½ years |
| 36 months | 3 years |
Special cases
Born at the end of a month
If you were born on the 31st and the current month is shorter, the calculator borrows the days of the previous month, which is the usual convention. For example, someone born on 31 January 2000 is 26 years and 28 days old on 28 February 2026.
Born on 29 February
In years without a 29 February, this calculator uses 28 February as the birthday when counting the days to your next birthday. Legal rules for leap-day birthdays, such as the date you officially turn 18, vary between countries, so check local rules where it matters.
Different ways of counting age
This calculator uses international age: you are 0 at birth and gain a year on each birthday. Some cultures have traditionally counted age differently, for example counting a newborn as 1. For official purposes, use the method that applies where you live.
Half and quarter birthdays
Your half birthday is six months after your birthday, when you are exactly half a year older. Someone born on 14 March is 31½ on 14 September. Use the half birthday calculator to see the date, the weekday and how many days are left.
Age calculator questions
How do I calculate my exact age?
Count the full years since your birth date, then the months since your last birthday, then the remaining days. The calculator above does this for you.
How old am I if I was born in 2000?
In 2026 you are 25 if your birthday has not happened yet this year, and 26 if it has. Enter your full date of birth for the exact age.
How many days old am I?
Enter your date of birth in the calculator above. It shows your age in total days.
How do I calculate age in months?
Multiply your full years by 12 and add the months since your last birthday. Someone who is 2 years and 6 months old is 30 months old.
How do I calculate age in Excel?
With the date of birth in A1, use =DATEDIF(A1,TODAY(),”Y”) for full years and =DATEDIF(A1,TODAY(),”YM”) for the extra months. The same formulas work in Google Sheets.
Related pages
- Half birthday calculator
- Months to years converter
- 6 months from today calculator
- How we calculate half birthdays
Last updated: 4 November 2026.