Answer

In Jain cosmology, the commonly counted Devalok are 12.

Explanation

These 12 are the main heavenly realms of the Vaimanika devas. Their names are traditionally listed as:

• Saudharm
• Ishan
• Sanatkumar
• Mahendra
• Brahma
• Brahmottar
• Lantaka
• Kapishtha
• Shukra
• Mahashukra
• Shatara
• Sahasrara

Spiritual Understanding

If we count the higher celestial divisions beyond these 12, then Jain texts also describe:

• 9 Graiveyak
• 5 Anuttar

So, if someone is asking about all upper celestial regions together, the total becomes 26.

Takeaway

• 12 Devalok = the main heaven realms
• 26 upper celestial realms = 12 Devalok + 9 Graiveyak + 5 Anuttar

If you want, I can also give you the full Jain cosmology chart in a simple way.