Printable Space Birthday

Get your class to work out their age in Mars years.


Elsewhere on this site, there's a space birthday calculator that works out for you how many "space years" old you are - you can see what your next birthday would be if you were born on Mercury, Venus, Mars, Jupiter, Saturn, Uranus or Neptune.

On this page, I've provided some worksheets that let you do the calculation yourself. If you're a teacher, you could get your whole class to work out their next Mars birthday, as part of a space-themed series of lessons.

You can download the worksheets here. Let me explain how they work:

The worksheet is in three parts, labeled A, B and C. You will need a calculator.

  • With Sheet A, you can convert a date to a number. The number is actually the number of days since the 28th of February, 1900. Note that this worksheet only works for dates between 1901 and 2099. If I tried to make the worksheet applicable for a wider range of dates, it would have become significantly more complex.
  • Use one copy of Sheet A to convert your date of birth to a number. Use another copy to convert today's date to a number.
  • Next, Sheet B is used to calculate your next space birthday. You enter the results from Sheet A into the appropriate cells of the worksheet. You also choose which planet you want to calculate your birthday for, and enter the number of days in that planet's year into the appropriate cell. The calculations on Sheet B finds the number of days from the 28th of Feb, 1900, until your next space birthday.
  • Finally, Sheet C does the opposite of Sheet A. So you take your space birthday from Sheet B, and convert it to a date.

I've preparing a video to show you how this all works. You can watch it here!