Interval reduction
Interval reduction is a mechanic that reduces the amount of time it takes to complete a skilling action. The time reduction is always based on the default interval. This means that, if a skill has a 5 second interval, a 10% interval reduction will always decrease the timer by 0.5 seconds. This is regardless of how much the interval is reduced already. The minimum action time is 0.25 seconds.
The game offers global interval reduction (which applies to every skill) and interval reduction for a specific skill. Both of these interval reductions are treated as equal. -10% global interval reduction has the same effect as, for instance, -10% Agility interval reduction. Global and specific reductions also stack.
Since the interval reduction is always based on the base action time, this means that the interval reduction becomes exponentially more impactful. The impact of the interval reduction can be calculated as follows:
[math]\displaystyle{ \text{Effective Reduction} = \frac{1}{1 - \text{Interval Reduction}} }[/math]
The graph above shows the relation between the interval reduction percentage, and the effect it has on the current interval. If a player equips -10% interval reduction on a skill with a base interval of 5 seconds, this deducts 0.5 seconds from the interval, or an effective reduction of 10% at 0% interval reduction.
However, if a player equips that same -10% interval reduction while they already have -50% interval reduction, the action time will go from 2.5 seconds to 2 seconds. This is an effective interval reduction of 20%.
This is also what the graph shows. The interval reduction gets a greater effect the higher the interval reduction already is. It is therefor important to use as many interval reduction items as possible, since their effects grow exponentially.
Global Interval Reduction
| Source | Type | Global Interval Reduction | Other Modifiers |
|---|---|---|---|
 Elite Pillar of Expertise |
 Agility Pillar |
-3% Interval for all non-Combat Skills | +8% Chance to Double Items Globally +40% Global GP (except Item Sales) +8% Global Mastery XP |
 Candelabra (Lit) |
 Item (Consumable) |
-3% Interval for all non-Combat Skills | +4% Global Mastery XP +3% Chance to Preserve Resources in Skills +4% non-Combat Skill XP |
 944 Hexes Mastered |
Mastery Bonus |
-3% Interval for all non-Combat Skills | -3% Attack Interval |
 Harold |
Pet |
-2% Interval for all non-Combat Skills | -0.1s Attack Interval -0.2s Monster Respawn Timer +3% Ammo Preservation +2% Chance to Double Items Globally +3% Chance To Preserve Potion Charge +5% Global GP (except Item Sales) +5% Accuracy Rating +5% Global Evasion +5% Global Mastery XP +50% Mastery Pool XP Cap +2% of Maximum Hit added to Minimum Hit +3% Rune Preservation +5% Slayer Coins +3% Chance to preserve Summoning Charges |
