Age Calculator
Enter a date of birth to get an exact age in years, months and days — plus the same age counted in months, weeks, days and hours, and a countdown to the next birthday.
- Exact to the day
- Next birthday
- Any two dates
- Free
Work out an age
Any date up to today
Blank = today
How an age is worked out
Years first, then months, then days
Count whole years from the birthday, then whole months from there, then the days left over. Someone born 15 March 1990 is 36 years, 5 months and 28 days old on 12 September 2026 — not 36.5 years, which hides the detail people actually want.
Months are not all the same length
A month after 31 January is 28 February, because there is no 31 February. That is why the day count never comes out negative here: each month is measured against its own real length rather than an average of 30.44 days.
The totals answer a different question
"36 years" and "13,330 days" are the same age said two ways. The day and week totals are exact counts including every leap day; the hour total assumes 24-hour days, so it ignores the hour that clocks gain and lose twice a year.
Questions people ask
How old am I exactly?
Enter your date of birth above and leave the second box blank. You will get your age in years, months and days, counted from your birthday rather than rounded, plus the same age in months, weeks, days and hours.
How does this handle a 29 February birthday?
If you were born on 29 February, this calculator treats 1 March as your birthday in ordinary years. On 28 February you are still shown as 11 months and 30 days past your last birthday, and you gain the year on 1 March. Some countries use 28 February instead, so a legal document may differ — this is the common convention in the US and UK, not a universal rule.
Can I work out my age on a past or future date?
Yes. Put the date you care about in the "Age on" box — how old you were when something happened, or how old you will be at a wedding or a deadline. It has to be on or after the date of birth.
Why is my age in months not just years times twelve?
It is, plus the extra whole months since your last birthday. Someone 36 years and 5 months old is 437 months, because 36 × 12 = 432 and then 5 more.
Does it count leap days?
Yes. The day and week totals are real calendar counts, so every 29 February you have lived through is included. That is why the total days for a 36-year-old is about 13,330 rather than 36 × 365 = 13,140.
What time zone does it use?
Your device's local date. An age is a calendar fact rather than a clock reading, so it does not shift as you travel — but if your device's date is wrong, the answer will be too.
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