Action Points are the method by which a character's Daily Powers are recharged. Each character has a gauge represented by a D20 in the middle of their Combat Action Bar. This gauge refills as the character gains more Action Points. When this bar is filled by the attainment of Action Points, a character's Daily Power is available for use. The use of a character's daily power depletes this gauge and a character must once again perform actions which grant Action Points to refill it.

According to the in-game tool-tips, each class can earn Action Points as follows:

• Barbarian - Dealing damage and using encounter powers
• Cleric - Healing or dealing damage
• Fighter - Taking or dealing damage and using encounter powers
• Paladin - Attacking foes and casting spells.
• Ranger - Dealing damage and using encounter powers.
• Rogue - Dealing damage
• Warlock - ???
• Wizard - Dealing damage

However, the tool-tips are misleading. For instance, Guardian Fighters can gain Action Points from blocking attacks, but do not gain Action Points from taking unguarded damage unless they have the [Martial Mastery] paragon feat.

Barbarian

• The first-tier heroic feat [Unstoppable Action] increases action point gain by 5/10/15/20/25% for dealing damage while you are [Unstoppable].
• The encounter power [Battle Fury] increases Action Point Gain.
• The encounter power [Indomitable Battle Strike] grants bonus Action Points when it kills a foe.
• The encounter power [Hidden Daggers] does not grants bonus Action Points when activated.^[1]

Cleric

• Charisma increases Action Point Gain.
• The first-tier heroic feat [Healing Action] increases action point gain by 1/2/3/4/5% whenever you use a healing ability.
• The encounter power [Prophecy of Doom] grants Action Points when its target dies.

Fighter

• Blocking grants the fastest AP gain, and attacking while blocking grants more than cleaving.
• Constitution increases Action Point Gain.
• The first-tier heroic feat [Action Surge] increases action point gain by 2/4/6/8/10% from Guarding attacks.
• The encounter power [Into the Fray] increases your party's Action Point Gain.
• The paragon feat [Martial Mastery] allows you to build Action Points by taking unguarded damage.

Paladin

• Charisma increases Action Point Gain.

Ranger

Rogue

• The first-tier heroic feat [Action Advantage] increases action point gain by 2/4/6/8/10% for dealing Combat Advantage damage.
• The paragon feat Cunning Stalker increases Action Point Gain when Stealthed.
• The paragon feat Action Rush gives your encounter powers a change to grant bonus Action Points.
• The paragon feat Thrill of the Kill grants Action Points for landing killing blows.
• The encounter power [Bait and Switch] creates a decoy that grants Action Points to the rogue when it is hit by an enemy.
• The class power [Tactics] increases Action Point Gain.

Warlock

Wizard

• Wisdom increases Action Point Gain.
• The first-tier heroic feat [Controlling Action] increases action point gain by 2/4/6/8/10% when using powers on a controlled target.
• The paragon feat [Critical Power] grants 1/2/3/4/5% of your total Action Points when you land a critical hit.