They say age is just a number, but it turns out that number can range wildly depending on what planet you’re on. And thanks to a nifty online calculator, you and your kid can figure out exactly how old you both would be if you were living on another planet.

Author Irene Diomi built the calculator based on NASA data and it’s extremely easy to use. All you have to do is enter the year you were born and it will tell you how old you would be if you were living on the other planets (including Pluto, which may or may not be considered a planet at this point, but who is counting anyway).

Of course, one Earth year is based on how long it takes our beloved planet to take a full trip around the Sun. As a result, other planets’ years are calculated differently. They can be longer or shorter depending on how long a revolution around the Sun takes. As a result, your age can range widely based on what planet you are looking at, as you can be nearly 150 years old on one planet and younger than your kid on another.

For example, if you are 30 years old on Earth, that means you wouldn’t have even reached your third birthday yet if you were a citizen of Jupiter.

And on Pluto and Uranus, you wouldn’t even be a one-year-old yet! But on Mercury, which is the closest planet to the Sun, you’d be eligible for any senior discounts, as you’d be 124 years old.

You can check out the calculator here