Exact Age Calculator
Find your exact age in years, months and days on any date, plus total months, weeks, days and hours, your next birthday and day-count milestones.
This calculator gives an age to the day: completed years, then the extra months and days since the last monthly anniversary of birth. It also converts the same span into total months, weeks, days and hours, counts down to the next birthday and lists day-count milestones such as the 10,000th day. Use it for forms that ask for age in years and months, or for school and sports cut-off dates.
How to use this tool
- Enter the date of birth.
- Leave "Age on" as today, or choose another date to see the age then.
- Read the age in years, months and days at the top.
- Scroll down for the totals, the next birthday and the milestone table.
Formula
Age = whole calendar months from birth to the target date (shown as years + months) + the days left over
Whole-month anniversaries are always anchored to the original birth date without passing the target date. An anniversary on a day the month lacks (the 31st in a 30-day month, or 29 February in a common year) moves to the month’s last day. Completed weeks = ⌊total days ÷ 7⌋ and total hours = days × 24, midnight to midnight.
Example
Someone born on 15 May 1990 is, on 29 October 2026, 36 years, 5 months and 14 days old. Counting 437 whole months from 15 May 1990 reaches 15 October 2026, and 14 more days reach 29 October. In total that is 13,316 days: 36 years of 365 days plus 9 leap days gives 13,149, and 15 May to 29 October adds 167. That is 1,902 weeks and 2 days. The 37th birthday falls on 15 May 2027, 198 days later.
Frequently asked questions
How is a 29 February birthday handled?
In years without 29 February the calculator treats 28 February as the anniversary, so someone born on 29 February 2000 turned 1 on 28 February 2001. Some legal systems use 1 March instead; if a legal age matters, check the rule where you live.
Why is my age in months not simply years × 12?
It is for the completed part: total months = years × 12 + the extra months. The leftover days are shown separately because months have different lengths.
Does the day of birth count as day one?
No. The calculator measures elapsed time, so on the day of birth the age is 0 days and the first birthday arrives one year later.
Can I find an age on a past or future date?
Yes. Set "Age on" to any date after the birth date, such as a school entry cut-off, a race day or a retirement date.
Last updated: 2026-10-30