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Age Difference Calculator

Created by Rita Rain
Reviewed by Dominik Czernia, PhD and Jack Bowater
Last updated: Jan 18, 2024


This age difference calculator lets you quickly determine the age gap between two people. In the text below, you can learn how to use the age gap calculator and find a few titbits about the age difference in relationships.

Age difference calculator

Using the age gap calculator, you're probably here to check the age difference between two people. Here's the fastest way to do it:

  1. Input the age of one person. By default, the unit is set to years, but you can choose a different one. The smaller the units, the more precise the result.

  2. Enter the age of the other person.

  3. The age difference will display at the bottom of the age gap calculator. You can convert the time to various units. Or you can use our time unit converter beforehand to have appropriate units of time.

You can also calculate age from years of birth, although this will be less accurate. In this case:

  1. Set the method to "From years of birth".

  2. Enter the first person's birth year.

  3. Input the year of birth of the other person.

  4. The age gap will show in the last field of the age difference calculator.

If you want a more precise result and know the dates of birth:

  1. Select "From dates of birth" in the first field of the age difference calculator.

  2. Enter the date of birth of one person.

  3. Enter the date of birth of the other person.

  4. The result will appear in the last field of the age difference calculator. The result will be more precise, and you can display it in the units of your choice.

  • We also have a birthday calculator that accurately tells you when your birthday is. If that sort of question might ever concern you, now you have a tool to be sure.
  • And we have a tool that tells your age in years, months, weeks, days, minutes and seconds, check out the chronological age calculator.

Age difference between Charles and Diana - an example using the age gap calculator

As we all know, there's nothing as fascinating as random bits of information about the British royal family. That's why we'll use the age difference between Charles and Diana as an example calculation in this age gap calculator.

  1. Since we know the exact dates of birth (thank you, Internet, what would we do without you) - let's choose "From dates of birth" in the first field of the age difference calculator.

  2. Let's enter Diana's date of birth - 1 July 1961. The easiest way is to type "Jul 1, 1961" and click "enter". You can also click the calendar icon and choose a year, a month, and a day.

  3. In the third field, let's enter Charles' date of birth - 14 November 1948 (type in "Nov 14, 1948").

  4. In the bottom field of the age gap calculator, we can find the result - Diana was 12 years, 7

months, and 15 days younger than Charles.

You might want to take a look at the day counter to count the days between two dates. And if you get lost in the maths of calculating your age from your date of birth, try out the age calculator and make your life easy.

This brings us to the fun-fact part of this tool - age differences in relationships.

How do I calculate age difference in years, months, and days?

The steps:

  1. Bring dates to the same month and day, e.g., change 03/05/2001 - 17/09/1978 to 17/09/2001 - 17/09/1978.

  2. Subtract the birth years, 2001 - 1978 = 23 years. Note the difference is below 23 years; this is 22 years.

  3. Bring dates to the same day and determine their month difference. Between 17/05/2001 - 17/09/2001, are 4 months.

  4. Subtract this from 12 months to get 8 months. Adjust by subtracting one month to get 7 months.

  5. Determine the difference in days between the original date and the changed date (03/05/2001 to 17/09/2001). This is 14 days. Subtract this from 30 days to get 16 days.

Note that this calculation assumes a 30-day month and doesn't consider leap years. For more accurate results, use Omni's age difference calculator.

Age difference in relationships

In the US, in around one-third of marriages, the age difference equals up to one year. In 19.6% of marriages, a husband is 2-3 years older than his wife, while only in 6.9% of married couples a wife is 2-3 years older than her husband. This exemplary data seems to confirm the age differential effect - a documented, cross-cultural phenomenon of men preferring younger women and women preferring older men.

Why does this pattern occur? According to evolutionary psychology, men favor young women because of their increased fertility, while women look for the ability to gain resources, which older men tend to have more of. All of this ensues that genes can be successfully passed on and that the offspring survives.

FAQ

How do I calculate the age difference between two people, given their ages?

To calculate the age difference between two people based on their ages, follow these steps:

  1. Determine age of person one, age1.

  2. Determine age of person two, age2.

  3. Subtract the two ages to get the age difference:

    age difference = age1 - age2.

  4. Take the absolute value of the difference to ensure a positive result:

    age difference = abs(age1 - age2).

What's the age gap formula for years of birth?

The age gap formula based on years of birth simply involves subtracting the year of birth for one person, year1, from the year of birth of the other person, year2:

age gap = abs(year1 - year2)

Taking the absolute value of the difference ensures that the result is positive.

What's the age difference between 01/01/1990 and 30/06/1995?

The age difference is 5 years, 5 months, and 29 days:

  1. Bring dates to the same month and day. From 01/01/1990 and 30/06/1995 to 01/01/1990 and 01/01/1995.

  2. Subtract the birth years, 1995 - 1990 = 5 years.

    Note the difference is greater than 5 years.

  3. Bring dates to the same day and determine their month difference. Between 01/01/1995 and 01/06/1995, are 5 months.

  4. Determine the difference in days between the original date and the changed date, 01/06/1995 and 30/06/1995, 29 days.

For more accurate results, use Omni's age difference calculator.

How do I calculate the age difference between 24 and 31 years?

To calculate the age difference:

  1. Subtract the two ages.

  2. Take the absolute value of the difference to ensure a positive result:

    age difference = abs(age1 - age2)

    age difference = abs(24 years - 31 years)

    age difference = 7 years.

Rita Rain
Method
From age
Age 1
yrs
Age 2
yrs
Age difference
yrs
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