Case 1
- Health pool
- 1000HP
- Damage reduction
- 40%
1,666.67EHP
Open with these valuesEffective Health Calculator
1,666.67EHP
Result: 1,666.67 EHPEffective health is your health bar seen from the attacker's side: how much raw damage it takes to drop you. Blocking half doubles it, blocking three quarters quadruples it. Enter the reduction your character sheet shows, not an armour rating — every game converts armour differently.
Worked examples
Case 2
- Health pool
- 500HP
- Damage reduction
- 60%
1,250.00EHP
Open with these valuesCase 3
- Health pool
- 1500HP
- Damage reduction
- 25%
2,000.00EHP
Open with these valuesHow it's calculated
EHP = health ÷ (1 − reduction)
- StepEnter your raw health, the number on the health bar.
- StepEnter the share of incoming damage you block, as a percentage.
- ResultRead the raw damage it now takes to kill you.
What this number means
Reduction multiplies, so the gain is not linear
EHP follows the curve 1 ÷ (1 − reduction), not a straight line. The first ten points add about 11 %, while the step from 80 % to 90 % doubles the pool.
It holds only for the damage type you entered
Resistances usually differ from one damage type to the next, so a single figure does not cover them all. Run it again with the reduction that applies to the hit you care about.
Enter the reduction, not an armour rating
Every game turns armour points into a percentage its own way, and this calculator does not do that step. Read the finished reduction off your character sheet.
100 % reduction is impossible here
At full reduction the divisor (1 − reduction) becomes zero and effective health would be infinite. The field therefore stops at 99 %, which is already a hundred times the raw health.
Commonly misread
40 % reduction means 40 % more effective health.
It means 1000 ÷ 0.60 ≈ 1666.67, two thirds more rather than 40 %. The divisor shrinks, so the gain outruns the percentage.
I typed my armour value of 100 into the reduction field.
The field takes the share of damage blocked, as a percentage, not armour points. Look up the reduction your character sheet already shows.
More health and more reduction are worth the same to me.
Health raises EHP in direct proportion, reduction on a steepening curve. Once you carry some armour, more reduction usually buys more.
My 60 % fire resistance protects me from this poison hit too.
Effective health holds only for the damage type it was computed for. Enter the reduction that applies to that hit.
Reference table
| Health, reduction % | What the reduction buys | EHP |
|---|---|---|
| 1000, 0 | No armour at all | 1000.00 |
| 1000, 25 | A third more than the bare health bar | 1333.33 |
| 1000, 40 | Two thirds more | 1666.67 |
| 1000, 50 | Blocking half doubles the health bar | 2000.00 |
| 1000, 75 | Blocking three quarters quadruples it | 4000.00 |
| 1000, 90 | Ten times the raw health | 10000.00 |
Questions
How do I calculate effective health?
Divide your raw health by one minus the damage reduction written as a fraction: EHP = health ÷ (1 − reduction). For example, 1000 HP with 40 % reduction is 1000 ÷ 0.60 ≈ 1666.67 EHP.
What is effective health (EHP)?
Effective health is the amount of raw incoming damage your character can absorb before dying, once damage reduction is taken into account. It is the size of your health bar from the attacker's point of view — usually larger than your raw HP, because each hit lands at reduced strength.
Why is each percent of reduction worth more at high values?
Because effective health follows the 1 ÷ (1 − reduction) curve, not a straight line. Going from 0 % to 10 % reduction multiplies your EHP by about 1.11, but going from 80 % to 90 % multiplies it by 2. The same ten points protect a larger and larger health pool, so reduction scales harder the more of it you stack.
Is more health or more damage reduction better?
Raw health raises effective health in direct proportion — 10 % more HP is always 10 % more EHP — while reduction raises it on a steepening curve. Once you already carry some armour, another chunk of reduction usually buys more survivability than the same investment in flat health. The only sure way to compare two builds is to compute the EHP of each and pick the bigger one.
Can damage reduction reach 100 %?
No. At 100 % reduction the divisor (1 − reduction) becomes zero, which would make effective health infinite, and no real game allows that. This calculator accepts reduction from 0 % up to 99 %.
Sources and last check
Information, not professional advice.