The age of a person is the difference between their date of birth and the current date. To calculate the age of a person in days, we need to subtract the date of birth from the current date and convert the result into a number of days.
One way to do this in Excel is to use the DATEDIF function, which returns the difference between two dates in various units, such as years, months, or days. The syntax of the DATEDIF function is:
=DATEDIF(start_date, end_date, unit)
where start_date and end_date are the two dates to calculate the difference between, and unit is the unit of time to return the difference in. For example, to calculate the difference in days, we can use "d" as the unit.
Another way to do this in Excel is to simply subtract the date of birth from the current date and use the INT function to round down the result to an integer. The syntax of the INT function is:
=INT(number)
where number is the value to round down. For example, to calculate the difference in days, we can use:
=INT(current_date - date_of_birth)
Procedures
To calculate the age of a person in days using Excel formula, we can follow these steps:
- Enter the date of birth and the current date in two separate cells, such as A2 and B2. Make sure the cells are formatted as dates.
- In another cell, such as C2, enter the formula to calculate the difference in days using either the
DATEDIFfunction or theINTfunction. For example:
=DATEDIF(A2, B2, "d")
or
=INT(B2 - A2)
- Press Enter to get the result. The cell will display the age of the person in days.
Explanation
To understand how the formulas work, let’s look at an example with real data. Suppose we have the following table in Excel:
| Date of Birth | Current Date | Age in Days |
|---|---|---|
| 01/01/2000 | 02/05/2024 | ? |
The date of birth is January 1, 2000 and the current date is February 5, 2024. We want to calculate the age of the person in days.
If we use the DATEDIF function, the formula in C2 will be:
=DATEDIF(A2, B2, "d")
This formula will return the difference between the two dates in days. Excel will internally convert the dates into serial numbers, which are the number of days since January 1, 1900. For example, the date of birth 01/01/2000 is equivalent to the serial number 36526, and the current date 02/05/2024 is equivalent to the serial number 44576. The difference between these two numbers is 8050, which is the age of the person in days.
If we use the INT function, the formula in C2 will be:
=INT(B2 - A2)
This formula will subtract the date of birth from the current date and round down the result to an integer. Excel will also internally convert the dates into serial numbers, as explained above. The subtraction will give the same result as the DATEDIF function, which is 8050. The INT function will then round down this number to the nearest integer, which is also 8050. This is the age of the person in days.
The final table will look like this:
| Date of Birth | Current Date | Age in Days |
|---|---|---|
| 01/01/2000 | 02/05/2024 | 8050 |
Other Approaches
There are other ways to calculate the age of a person in days using Excel formula, such as using the YEARFRAC function, which returns the fraction of a year between two dates, or using the DATE function, which returns the serial number of a specific date. However, these methods may not be as accurate or simple as the ones explained above. Therefore, we recommend using either the DATEDIF function or the INT function to calculate the age of a person in days using Excel formula.
