How Old Am I Calculator

Created by Davide Borchia
Reviewed by Anna Szczepanek, PhD
Last updated: Jan 09, 2023

Do you want to know how to calculate how old you are without effort? Our how old am I calculator is the perfect tool for this: you can find your age in many different units and even change the date to check how old you are on any date of your choice. And if you don't like the results because it's too high, don't worry: we're sure you're aging like fine wine!

How to calculate how old am I?

To calculate how old you are, you only need to do three things:

• Choose the date of birth;
• Choose the current date; and
• Subtract them.

The result is your age. However, dates are slightly tricky to subtract: here is how to do it:

1. Subtract the number of days in the current date and the number of days of your birthday:
• If the number of days of the current date is greater than the one of your birthday, go on!
• If the number of days of the current date is smaller, you have to "borrow" a month: decrease the number of months of the current date by $1$, and add $30.5$ days to the number of days, then proceed with the subtraction.
2. Subtract the number of months between the two dates. Use the same procedure we've seen above: if you need to "borrow" a year, add $12$ months to the current date.

3 Subtract the number of years. No problems here: if your question is "how old am I" then the current year will always be larger than your birth year.

An example of how to calculate how old is someone

Let's calculate how old someone is if they were born on, for example, the 12th September 1995, and if today is the 8th January 2024. Let's subtract the days first:

$\begin{split} n_\mathrm{days} &= 8-12 \\ &= (8+\textcolor{blue}{30.5})-12\\ &=38.5-12=26.5 \end{split}$

We had to borrow $\sim30$ days from the months. Next step, subtract the month. We need to take one month off from the current date. Consider January to be month number $1$. We have, then:

$\begin{split} n_\mathrm{months}& = (1-\textcolor{red}{1})-9\\ &=(0+\textcolor{blue}{12})-9 \\ &=12-9= 3 \end{split}$

We had to borrow 12 months from the year, which leaves us with the following:

$\begin{split} n_\mathrm{years}& = (2023-\textcolor{red}{1})-1995\\ &=2022-1995 = 27 \end{split}$

This person would be approximately $27$ years, $3$ months, and $26$-$27$ days old (depending on the moment of the day!). It's not that complicated, isn't it?

Other age calculators

Our age is always of interest: we count it and celebrate it as it grows (though after a while, we'd like it to stop). Omni created a suite of tools to help you with this mathematical problem. Try the other related tools:

FAQ

How many days old am I on my 30th birthday?

On your 30th birthday, you are 10,957 days old (approximately). To calculate this result, simply multiply the approximate number of days in a year (365.25) by 30, the number of years you spent on this planet:
n = 365.25 × 30 = 10,957.5
That half day can be rounded up or down according to the moment of the day.

How do I calculate how old am I today?

To calculate how old you are today, be sure to know the date of your birthday and today's date. Then:

1. Subtract the number of days of your birthday from the current one. If the result is negative, carry over 30.5 and reduce the months of the current date by 1.
2. Subtract the number of months. You may have to carry over 12 months and reduce the number of years by 1.
3. Subtract the current year (eventually adjusted by carryovers) and your birth year.

That's it!

How many months old am I?

To calculate how many months old you are, follow these easy steps:

1. Calculate how old you are by subtracting the chosen date and your birth date. Remember that you may have to carry over 30.5 days or 12 months if the results of the corresponding subtractions are negative.
2. Multiply the number of years by 12.
3. Divide the number of days by 30.5.
4. Sum the results to find your age in months.

How many hours old I am?

To find how many hours old you are, you must first find your age in days. To do so:

1. Subtract the current date from your birth date. You may have to adjust the subtractions by carrying over 30.5 days (the approximate length of a month) and 12 months.
2. Multiply the number of days by 24 to find your age in hours.
3. You can also consider the time of your birth and the current date. The previous result, however, is already an approximation!
Davide Borchia
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