Monday 16 February 2015

Vulcan birthday calculator

When is it my Vulcan birthday?
For the exact length of a Vulcan year check below.


Please insert your date of birth or age and the Vulcan year estimate:

DOB day:
DOB month:
DOB year:
Alt: Age:
Vulcan year length:

Vulcan years: 124.1
Next birthday: 5 Jul 2016

How long is a Vulcan year?

I have found three dates:
  1. According to Memory Alpha Gene Roddenberry gives a Vulcan year as 456 ± 33 Terran days, which would make it a freezing iceblock.
  2. Memory Beta has different, more realistic values. The only sourced one is 266.4 days, which is still on the chilly side for 40 Eridani.
  3. On Star Trek Star Charts (2002) page 58 the year lasts 248 days.
Additionally, we know the following information:
  • Vulcan is a warmer planet than Earth
  • Vulcan (T'Khasi) orbits an orange star (Alam'ak, 40 Eridani A, spectral class: K1V), which is much cooler than Sol, a yellow star (G2V)
Consequently, it should be around 200 days.
However, there is the possibility that the definition of year (tevun) might not be an tropical orbital period around 40 Eridani. If there were little axial tilt and a near circular orbit, seasonal difference would be less pronounced (Game of Thrones's years Westeros can be explained this way in conjuction with short Milankovitch cycles).
PS. If you have any useful figures or facts about the year length, please do share!


  1. What a fantabulous post this has been. Never seen this kind of useful post. I am grateful to you and expect more number of posts like these. Thank you very much.

  2. The star chart you posted has the orbital period as 248 YEARS not days!!

    1. Wow. You are right. However, it is most likely a typo (as in they meant days). Coincidentally, Pluto has a period of 248 years.

    2. Actually, the whole book is bizarre: it tries to map places based on tenuous sloppy script-writing (after all, travel time to Qo'noS seems to alter and the primitive Kazon catch up with Voyager for multiple seasons).

  3. The star chart you posted has the orbital period as 248 YEARS not days!!