How Old Was I On This Date Calculator
Figure out how old you were on any date using the calculator below. Calculate your age in years, months, days, or even seconds.
Your Age On This Date:
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Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.
How to Figure Out How Old You Were
You can calculate your age on a given date using a calendar and some basic math. To figure out your age, follow a few easy steps:
Step One: Identify the Necessary Dates
You’ll need to determine your birth date and the date on which you want to know your age. You will use these two dates for your calculation.
Step Two: Break Down the Dates
The next step is to convert the dates into three components: year, month, and day. The month should be in numeric form, so January is month number one.
For example, if your birth date is November 15, 1990, it can be broken down into:
- Year: 1990
- Month: 11
- Day: 15
Similarly, to find how old you were on September 20, 2023, then you can break that date down into:
- Year: 2023
- Month: 9
- Day: 20
Step Three: Calculate the Difference in Years
The third step is to subtract the birth year from the specific year to find how many years there are between the dates.
Continuing the example above:
2023 – 1990 = 33 years
Step Four: Adjust for the Month and Day
Next, you’ll need to check if the specific date’s month and day are before the birth date’s month and day within the same year.
If the specific date’s month and day is before the birth date’s month and day, then subtract one year from the difference calculated in step three. This is necessary because the full year hasn’t elapsed yet.
In our working example, since the birthdate of November 15, 1990 falls later in the year than September 20, 2023, 1 year needs to be subtracted from the difference found in step three.
33 – 1 = 32 years
Step Five: Calculate the Exact Months and Days
To find exactly how old you were on the specific date, you also need to consider the difference in months and days.
If the specific month is after the birth month, then you can calculate the additional months in age by subtracting the birth month number from the specific month number.
If the specific month is before the birth month, then you’ll add 12 to the specific month number to account for the year that was subtracted in step four, and then, subtract the birth month number.
For day calculation, if the day of the month in the specific date is before the day of the month in the birth day, then subtract one from the month and calculate the day difference.
If the day of the month is after the day of the month in the birth date, then add the number of days between this day of the birthdate and the day number of the specific date in the month after the birth month. In this case, also subtract 1 from the number of months.
You can also use our date range calculator to figure out how many days there are between the dates.
For example, let’s calculate how old someone born on November 15, 1990 was on September 20, 2023:
Let’s start by identifying the dates:
- Birth Date: June 15, 1990
- Specific Date: September 20, 2023
Then, let’s break down the dates:
- Birth Date: Year = 1990, Month = 6, Day = 15
- Specific Date: Year = 2023, Month = 9, Day = 20
Next, let’s calculate the difference in years:
2023 – 1990 = 33 years
Then, we need to adjust for the month and day. Since September (9) is before November (11), we need to subtract one year:
33 – 1 = 32 years
And finally, let’s calculate the exact number of months and days:
For the months, since September (9) is before November (11), we need to add 12 months to the birth date month number, and then subtract:
9 + 12 – 11 = 10 months
For the days, since the day in the birth date (15) is smaller than the day in the specific date (20), we can simply subtract:
20 – 15 = 5 days
So, this person would be 32 years, 10 months, and 5 days old on November 20, 2023.
You can also use our age difference calculator to figure out the age gap between two people.