Toughness Calculator
One number that matters when the hit lands: effective HP. Convert life, armor and resistances into the raw damage you survive at your content's enemy level.
How it works
armorDR = armor ÷ (armor + K × enemyLevel) resDR = resistance ÷ 100 (capped) EHP = life ÷ (1 − armorDR) ÷ (1 − resDR) survived = EHP ÷ incoming raw hit
The K constant parameterizes the armor curve — it's the model's main [VERIFY] because Blizzard's scaling has moved between seasons. Fortify stacks add to the life pool directly. Methodology.
FAQ
What is effective HP (EHP)?
How much raw damage it takes to kill you after mitigation. Armor and resistances divide incoming damage, so a tankier build "buys" virtual life — EHP is the common currency for comparing Life, armor and resist upgrades.
What armor coefficient should I use?
The armor curve constant K depends on the enemy-level scaling Blizzard uses, which has changed across seasons [VERIFY]. The default is a community-style placeholder; if your survivability in-game disagrees, adjust K until two test hits match, then trust the model.
Why am I still getting one-shot above my EHP?
Elite and boss attacks carry damage multipliers, and some mechanics bypass portions of mitigation. EHP is a floor against normal hits — build a 2–3× buffer for Pit-tier content. See <a href="/guides/survival-math/">survival math</a>.