How to Calculate Age: A Complete Guide for Excel and SQL

Do you need to know how to calculate your age for a dataset or a project? While an online age calculator is great for quick checks, professionals often need to calculate age using software. This guide covers how to calculate age by dob (date of birth) using Excel, SQL, and manual methods.

How to Calculate Age in Excel

Excel is a powerful tool for date calculations. If you want to calculate age in excel, there are specific formulas you can use.

Using the DATEDIF Function

The most common way to calculate age from date of birth in excel is the DATEDIF function.

=DATEDIF(A1, TODAY(), "y")

Here, A1 represents the cell containing the date of birth. This formula will calculate age in completed years.

Using YEARFRAC

Another method to excel calculate age from dob is YEARFRAC.

=INT(YEARFRAC(A1, TODAY()))

This excel formula to calculate age from date of birth is very accurate and handles leap years well.

Calculate Age on a Specific Date

To excel formula to calculate age on a specific date, replace TODAY() with your target date cell. For example, to calculate age in excel in yyyy/mm/dd format comparisons, ensure both cells are formatted correctly as dates.

=DATEDIF(A1, B1, "y")

Where B1 contains your specific date for age calculation.

How to Calculate Age in SQL

For database administrators, knowing how to calculate age from date of birth in sql is essential.

Basic SQL Query

In standard SQL, you might use:

SELECT DATEDIFF(hour, birth_date, GETDATE()) / 8766 AS AgeYears

However, syntax varies by database system. In MySQL, you would use TIMESTAMPDIFF(YEAR, dob, CURDATE()).

Specialized Calculations

Sometimes you need to calculate age from ic numbers in singapore before 1968 or other unique ID formats. This requires parsing the ID string to extract the birth year first, then applying the calculate age logic.

Manual Calculation Methods

If you are without a computer, you might ask how to calculate age manually.

  1. 1

    Write down the dates: Current Date (YYYY-MM-DD) and Birth Date.

  2. 2

    Subtract Years: Current Year - Birth Year.

  3. 3

    Adjust for Month/Day: If the current month/day is before the birth month/day, subtract 1 from the result.

This logic is the basis for any age calculator by date of birth.

Advanced Calculations

Calculate Gestational Age

To calculate gestational age, doctors usually count from the first day of the last menstrual period (LMP). To calculate gestational age from lmp, you add the number of days since that date to calculate the weeks of pregnancy.

Calculate Metabolic Age

To calculate metabolic age, you need more than just a birth date. It involves analyzing your Basal Metabolic Rate (BMR) compared to the average for your age group.

Summary

Whether you need to calculate age in excel, execute a SQL query, or just check your own age, knowing the methods is helpful. For the fastest result without formulas, simply use our age calculator at the top of the page.