Calculate Your Age On Other Planets!
Do you wish to get younger or older? Travel to an extraterrestrial planet!
Fill in your date of birth below in the format mm/dd/yyyy and then click on the “Calculate Age” button. As soon as you click the button, your age on other worlds will automatically fill in. You will notice your age is different on different planets and that your age in days and years varies drastically. You will also notice when your next birthday on each planet will be. The date given is an Earth date. NOTE: your birthday might be a day before or after, this is due to the leap years (your birthday remains the same but the days in a year increase by 1 every 4 years for Earth and similarly years on other planets are also not exact). Click on the “Clear” button to reset the calculator. Get ready to be amazed!
Date Of Birth: 

Planet 
Age In Days 
Age In Years 
Next Birthday (Earth Date) 
Mercury 

Venus 

Earth 

Mars 

Jupiter 

Saturn 

Uranus 

Neptune 

Pluto 
This calculator program is made by me (Dirgh Shah) using JavaScript.
The Time Of Our Lives
Your age changes, sometimes by a lot, depending on the planet. That brings up the question of what is age, is it just a number? Age is just a measure of the number of time intervals a person has lived or existed in. That raises another question: how do we define time intervals which we measure? What is a day? What is a year?
Does 24 hours or 1440 minutes or 86400 seconds or 86400000 milliseconds define a day? No. A day is defined by the time taken for Earth or any other planet to complete 1 rotation around its axis. It takes 24 hours for Earth to complete 1 rotation and so a day on Earth is 24 hours long. The length of a day is different on different planets because the rate of rotation of planets varies. There is no general law governing the speed of rotation of the planets, it all depends on the amount of spin in the initial matter which then formed into a planet. Venus takes 243 Earth days to rotate once around its axis while Jupiter only takes 10 hours.
Similarly, a year is defined by the period is the time taken to complete 1 revolution around the sun. Earth takes 365.26 Earth days to complete one revolution. The time taken to complete 1 revolution depends on the planet’s distance from the sun. The closest planet Mercury takes only 88 Earth days while Pluto, the dwarf planet furthest from the sun, takes about 248 Earth years to completely travel around the Sun.
The table below shows the different rates of rotation and revolution of all Planets in terms of Earth days and Earth years:
days 
days 

days 
days 

day 
days /1 year 

days 
years 

days 
years 

days 
years 

days 
years 

days 
years 

days 
years 
Math Behind Calculation Your Age On Other Planets
The mathematics behind this calculation is very basic – simple cross multiplication. Let’s try 1 calculation.
Agent Smith is 20 years old on Earth. If 1 Jovian Year (year on Jupiter) is equal to 11.86 Earth years, then 20 Earth years is equal to how many Jovian years? To find out you do the normal cross multiplication:
Jovian Years  Earth Years 
1  11.86 
?  20 
Therefore, your age on Jupiter is equal to 20/11.86 which approximately is 1.67 Jovian years.
Math Behind Calculating Your Next Birthday Date
I used a simple logic to calculate the next date of your birthday. I will explain this logic by showing a simple calculation.
Your age in days is a multiple of the number of days in a year. For example, On Earth, 1 year is equal to 365.25 days and so when Agent Smith completed 20 years, his age in days was 7305 which is a multiple of 365.25 (365.25 × 20 = 7305). Using this logic, the days left from today for your birthday is the remainder of your age in days at the moment divided by the days in a year plus 1 for today. The formula used to calculate the days remaining for your next birthday on Earth can be written as:
Days_Left = (365.26 – [Your_Age_In_Days % 365.26]) +2.
Days_Left = 367.26 – (Your_Age_In_Days % 365.26)
(% sign used here denotes the function mod which returns the remainder of a division)
Generalized Equation:
Days_Left = Days_In_A_Year + 2 – (Your_Age_In_Days % Days_In_A_Year)