Turn Undead

Turn Undead Mechanics
Turning undead consists of the following checks: Destroying undead: If you have twice or more as many effective cleric levels (Turning value) as the undead have hit dice, you destroy any that you would normally turn. The Mighty Turning enhancement allows you to destroy any undead that has less or equal hit dice to the turning check result.
 * 1) Turning check: A charisma check (1d20 + your charisma modifier) determines the hit dice of the most powerful enemy you can affect (See table below.)
 * 2) Turning damage: Total number of hit dice you can affect is 2d6 + effective cleric level + charisma modifier (Paladins get a -3 to level.)

Bonuses to Turning
There are also items, spells, and enhancements which can help increase your turning ability by boosting your effective cleric level for turning. These bonuses are added all parts of the turn undead calculation: Note: The first 4 item enhancements do not stack with each other.
 * Eternal Faith items
 * Hallowed items
 * Sacred items
 * Silver Flame items
 * Insightful Faith items
 * The spell Seek Eternal Rest will add a stacking +4 sacred bonus to your turning value.
 * The enhancement Improved Turning (RS/KotC) can add from 1 to 3 points to your turning value.
 * The feat Improved Turning will add 1 to your turning value.
 * Insightful Faith items
 * The spell Seek Eternal Rest will add a stacking +4 sacred bonus to your turning value.
 * The enhancement Improved Turning (RS/KotC) can add from 1 to 3 points to your turning value.
 * The feat Improved Turning will add 1 to your turning value.
 * The feat Improved Turning will add 1 to your turning value.

Sources of Extra Turns
Note: The item enhancements do not stack with each other.
 * Lesser Turning items
 * Minor Turning items
 * Alchemical Conservation items
 * A Cleric or Paladin possessing Turn Undead gains additional charges equal to his/her charisma modifier.
 * The enhancement Extra Turning (RS/KotC) grants an additional +1 turning charge per rank.
 * The epic destiny enhancement Endless Turning grants an additional +1 turning charge per rank.
 * The feat Extra Turning grants an additional +4 turning charges, but can only be taken once.
 * The Endless Turning enhancements (RS/Divine Crusader), which returns one charge per 120 seconds, time between returned charges is reduced with additional ranks.
 * The epic destiny enhancement Endless Turning grants an additional +1 turning charge per rank.
 * The feat Extra Turning grants an additional +4 turning charges, but can only be taken once.
 * The Endless Turning enhancements (RS/Divine Crusader), which returns one charge per 120 seconds, time between returned charges is reduced with additional ranks.

Alternate uses of Turn Undead charges
Any ability which reads as "Channel divinity" requires a Turn Undead charge to activate. All abilities cost a single turn attempt to use, unless otherwise noted.

Paladin

 * Sacred Defender
 * Divine Righteousness, which grants temporary hit points equal to your charisma modifier, and grants a +100% sacred bonus to threat generation
 * Glorious Stand, which grants, absorption of negative and elemental energy, double incoming healing, and immunity to weapon effects.
 * Eternal Defender, which, whenever you are incapacitated but not killed, you expend 2 turn undead charges, and are healed for 250 positive energy.
 * Knight of the Chalice
 * Holy Light, which deals a medium amount of light damage to nearby undead.
 * Divine Might, which grants an insight bonus to strength equal to your charisma modifier for a short time.
 * Rally, which removes fear, grants a bonus to saves versus fear, and grants a small bonus to attack or damage.
 * Holy Retribution, which deals additional base damage and for evil creatures be destroyed or take 100 holy damage and -6 to all ability scores.

Cleric

 * Radiant Servant
 * Positive Energy Burst, which heals targets around you and removes negative levels and stat damage.
 * Divine Cleansing, which removes certain status effects from the target.
 * Divine Healing, which restores health over time.
 * Purge Dark Magic, which removes effects from the target.
 * Martyrdom, which when you are killed expends 4 turn undead charges, and heals nearby allies for a large amount.
 * Positive Energy Aura, which creates a healing over time zone around you.
 * Reactive Heal, which applies a buff which is consumed when the target drops below 50% hp, consumes itself and heals the target. It also grants immunity to its own effect for 3 minutes.
 * Divine Disciple
 * Divine Vitality, which restores spell points to the target.

Divine Crusader

 * Confront Any Foe, which inflicts extra light damage on a successful hit.