Sometimes you need to know how old someone was on an earlier date. You may be checking a school record, family event, news story or old photograph.
You need two dates: the person’s date of birth and the past date you want to check.
Choose the past date
The past date is called the reference date. It could be:
- A wedding date
- A school admission date
- The date of an exam
- The date of a family event
- The date another person was born
Count from birth to that date
Start with the date of birth. Count full years, then full months, then the days left until the past date.
This is the same calendar method used by the Age Difference Calculator. Enter the birth date and the past date as the two dates.
Example
A person was born on 8 May 1995. You want to know their age on 20 January 2020.
Compare those two dates. The result is the person’s exact age on 20 January 2020.
What if the past date is before birth?
The person was not born yet. Do not describe the result as their age. State clearly that the chosen date came before the date of birth.
Check old records carefully
Old records may contain spelling errors or only a birth year. If the full date is not known, say that the answer is an estimate.
Use the Age Difference Calculator