File:Damage formula 1.9.1.svg

Summary
Damage formula, based on the information on Java Edition 1.9.1

totalDamage = damage \times (1 - \frac {\max( {\frac {defensePoints} {5}   },    {defensePoints -\frac {damage} {2+\frac {toughness} {4}     }    })  }  {25} )
 * LaTeX formula: