How to Calculate Your Exact Age
Years, months and days — and how leap years affect them.
Published by QuickUtilaUpdated 2 min read
Your age in years is easy to work out, but forms, medical records and milestones sometimes need it in years, months and days. The method below gives the same answer as the Age Calculator.
Step 1: Count the completed years
Subtract the birth year from the current year. If this year’s birthday hasn’t happened yet, subtract one more.
Step 2: Count the completed months
Count the months from your most recent birthday to today. A month is complete when the same day of the month comes around again — for a birthday on the 15th, each month completes on the 15th.
Step 3: Count the remaining days
Count the days from the last completed month to today.
- 1Years: 2026 − 1990 = 36 (the March birthday has passed)
- 2Months: March 15 → September 15 = 6
- 3Days: September 15 → September 24 = 9
Therefore: The exact age is 36 years, 6 months and 9 days.
Months with fewer days
If you were born on the 31st, some months have no 31st. In that case the last day of the month is used instead. Someone born on January 31 completes a month on February 28 (or 29 in a leap year), then on March 31.
Leap year birthdays
People born on February 29 have a calendar birthday only in leap years. In other years, the Age Calculator counts February 28 as the anniversary. Legal rules differ between countries — some use March 1 — so check the rule that applies if the date matters officially.
Age in total days or weeks
To find your age in days, count every calendar day from your birth date to today, including the extra day in each leap year. Dividing by 7 gives your age in weeks. Doing this by hand is slow, which is where the calculator helps: it shows totals in months, weeks and days alongside your exact age.