Critical hits are characterised by a large, bold and italic font. The colour of the hitsplat indicates the combat style used, with orange for Melee, green for Ranged, and blue for Magic.
The Biting perk has a 2% per rank chance to force a hit to be a critical hit. Warpriest of Tuska armour has a set effect which adds a chance to force a critical hit - 1% per part worn (minimum 3 parts).
Before the combat updates of 14 July 2014, critical hits functioned via a critical bonus, a probability of how often a player would land a critical hit. There was a separate bonus for each of Melee, Ranged, and Magic, and each bonus could be increased by wearing jewellery, capes, scrimshaws, and certain weapons. These critical bonuses replaced the pre-EoC equipment bonuses (Strength bonus, Ranged strength and Magic damage).
When a player landed a critical hit, they dealt 100% to 105% of their attack's maximum damage. This applied to both abilities and auto-attacks.
Critical bonuses were changed to damage bonuses on 14 July 2014.