What is my age?

Age, in general, is the amount of time for which something existed.

A person's age is the time that has passed from the moment they were born. The time before birth is called the gestational age (the age of a pregnancy is counted from conception).

In most parts of the world, a baby starts life at 0 and becomes 1 year old on the first anniversary of their birth. However, in some countries (notably in Korea), age is counted differently. In the text, we'll use the most common system.

Let's see how to use the age calculator to help you answer the question - "what is my age?".

How old are you? Calculate age from the date of birth

We'll now learn how to calculate age from date of birth without help from the age calculator.

Let's say it's 15.01.2021, and you were born on 5.12.2000. Let's time-travel and count:

Start on your date of birth. Go forward in time - check how many years you have to add to reach your last birthday:
Your last birthday was on 5.12.2020. Subtract the years:
5.12.2020 - 5.12.2000 = 20 years
Now we're on 5.12.2020. Add as many full months as you can but don't go too far into the future (stop before you reach today).
In this example, if we go 1 month forward from 5.12.2020, we land on 5.01.2021 and so have to stop time traveling in months.
Add the remaining days. We're on 5.01.2021. We can simply subtract days:
15.01.2021 - 5.01.2021 = 10 days
Add the results from steps 1-3. We get 20 years, 1 month and 10 days.

Example

Understanding Age Calculations

Age calculations are commonly used to determine a person's current age, find birth years, calculate age differences, and predict future ages. These calculations are essential in fields like healthcare, education, finance, and everyday planning.

The key concepts of age calculations include:

Calculating Age from Birth Year: Subtracting the birth year from the current year determines a person’s age.
Finding Birth Year from Age: If a person's age is known, subtracting it from the current year gives the birth year.
Age Difference: Used to compare ages between individuals, often in family relationships, schooling, or work environments.

Calculating Age from Birth Year

To determine a person’s age:

Subtract the birth year from the current year.

Example: If born in 1995 and the current year is 2025: \( 2025 - 1995 = 30 \) years old.

Finding Birth Year from Age

To determine the birth year when given a person’s age:

Subtract the age from the current year.

Example: If a person is 25 years old in 2025: \( 2025 - 25 = 2000 \) (birth year).

Calculating Age Difference

To find the age difference between two people:

Subtract the birth year of the younger person from the birth year of the older person.

Example: If one person was born in 1990 and another in 2000: \( 2000 - 1990 = 10 \) years apart.

Determining Age in a Specific Year

To determine how old someone will be in a future or past year:

Subtract the birth year from the target year.

Example: If born in 2005 and asked for age in 2030: \( 2030 - 2005 = 25 \) years old.

Real-life Applications of Age Calculations

These calculations are widely used in various real-world scenarios, such as:

Determining eligibility for driving, voting, or retirement.
Calculating age differences in relationships and family history.
Planning milestones such as birthdays and anniversaries.
Age-based qualification for education, employment, and benefits.

Common Operations in Age Calculations

When working with age calculations, the following operations are commonly used:

Adding or subtracting years to determine future or past ages.
Calculating age differences between individuals.
Estimating eligibility for legal or professional milestones.

Example: If a child is born in 2010, they will turn 18 in \( 2010 + 18 = 2028 \).

Age Calculation Examples Table
Calculation Type	Description	Steps to Calculate	Example
Calculating Age from Birth Year	Find a person’s current age based on their birth year.	Subtract the birth year from the current year.	If born in 1995 and the current year is 2025: \( 2025 - 1995 = 30 \) years old.
Finding Birth Year from Age	Determine the birth year when given a person’s age.	Subtract the age from the current year.	If a person is 25 years old in 2025: \( 2025 - 25 = 2000 \) (birth year).
Age Difference Between Two People	Calculate the age gap between two individuals.	Subtract the younger person’s birth year from the older person’s birth year.	If one person was born in 1990 and another in 2000: \( 2000 - 1990 = 10 \) years apart.
Determining Age in a Specific Year	Find out how old someone will be in a future or past year.	Subtract the birth year from the target year.	If born in 2005 and asked for age in 2030: \( 2030 - 2005 = 25 \) years old.
Real-life Applications	Using age calculations in everyday life.	Determining eligibility for driving, voting, or retirement. Calculating age differences in family history or relationships. Planning milestones such as birthdays and anniversaries.	If a child is born in 2010, they will turn 18 in \( 2010 + 18 = 2028 \).