Mutagenesis calculator

The calculator has been moved to www.mutanalyst.com.

Vulcan birthday calculator

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

Caculator

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!