Tinker 
How to use the age calculator
Enter the date of birth, then the date you want the age on. Set it to today for your current age, or any other date to check an age at a past event or future deadline.
You get the exact age in years, months and days, totals in months, weeks and days, and the date and countdown to the next birthday.
How the age is worked out
The calculator finds the latest monthly anniversary of the birth date that falls on or before the 'age on' date. The number of whole months to that anniversary gives the years and months; the days from that anniversary to the target date are the leftover days. If the birth day does not exist in a month (for example the 31st, or 29 February), the anniversary falls on the last day of that month.
Total days is the calendar-day difference between the two dates, so leap years are counted exactly.
Worked example
Born 15 May 1990, age on 10 March 2024: the last monthly anniversary is 15 February 2024, which is 405 months (33 years, 9 months) after birth. From 15 February to 10 March 2024 is 24 days (February 2024 has 29 days). Result: 33 years, 9 months, 24 days.
That is 12,353 days lived, or 1,764 full weeks. The next birthday is 15 May 2024, 66 days away.
Tips
Forms asking for age almost always mean full completed years. Month-and-day results can differ by a day between tools because month lengths vary; this tool uses the anniversary method described above.
Frequently asked questions
Does the calculator handle leap years?
Yes. Total days are counted from real calendar dates, so every 29 February is included.
When does someone born on 29 February have a birthday?
Here, on 28 February in non-leap years. Some places legally use 1 March instead.
Why do months and days sometimes look uneven?
Months have 28 to 31 days, so leftover days are counted from the most recent monthly anniversary of the birth date.
Can I find an age on a past date?
Yes, set the 'age on' date to any date on or after the birth date.