Spirea's Diablo II Resource

Energy Shield

Energy shield is a sorceress skill in the lightning tree that reduces some of the damage taken at the cost of mana.
Xinhuan published a paper on HP/Mana Balance which introduced the concept of Effective Hit Points (EHP). This calculator is based on that paper.
There is a similar calculator on that page, and both should produce similar results.

HP (Life)
Mana
Vulpine %
Energy Shield

  For melee For non-melee
Ideal ES % for melee
EHP
Max EHP

A few questions you might ask while using this calculator:
(I am going to assume that you have read Xinhuan's paper)

  1. Should I increase my Energy Shield level?
    If your ES % is below the ideal ES %, that means you are going to run out of hp before you run out of mana.
    So increasing the energy shield level should increase your EHP.

  2. Should I increase my life or energy?
    Again, if your ES% is below the idea ES %, that means you are going to run out of hp first.
    So increasing hp will increase EHP, while increasing mana will not.
    For other cases, try increasing the life/mana in the calculator by 2
    to see which of them will increase the EHP more.