Your combat level summarises your fighting power for quests and for the Wilderness's ±10 attack bracket. It is 0.25 × (Defence + Hitpoints + half your Prayer level) plus 0.325 × your best attack contribution — Attack + Strength for melee, or 1.5 × Ranged, or 1.5 × Magic — rounded down, with a minimum of 3. Training any combat skill (including Prayer and Hitpoints) raises it.