Note: Some of this analysis is speculation, as Jagex refuses to reveal the actual formulae used.

Additional note: Statistical testing reveals that the model as currently implemented likely needs to be revised. More on the discussion page for this article.

Calculator Edit

This calculator implements the calculations discussed below. It has direct support for the special abilities of four raiders (Saurus Slink, Ranger of the North, Berserker, Black Knight) and two rooms (Corrosive Slime, Stone Golem). Other abilities (Witch, Dryad, Enchantress, Zealot, Sorceress) and effects, whether temporary (Tripwire Bell, etc.) or permanent (Rot Worms, etc.) must be handled manually with the modifier boxes. If you would like a downloadable version with slightly less functionality (Windows only), you can get one here.

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Probabilities Edit

The probability of winning an encounter between a raider and a room depends on a variety of factors. These are the current stats of the raider and the room, which interaction is chosen by the raider, and any special abilities used by the raiding party.

The outcome of each interaction is determined by the result of a series of "rolls" between two corresponding stats:

Raider Stat Room Stat Probability of raider winning roll
DA Atk Attack DA Def Defence Attackprobability
DA Def Defence DA Atk Attack Defenceprob
DA Dodge Dodge DA Snare Snare Dodgeprob
DA Snk Sneak DA Detect Detect Sneakprob

Guardians Edit

To avoid setting off a guardian the raider must win the roll corresponding to the guardian's stat, giving a probability of success of:

Tripwire Bells: Tripprob
Halls of Glass: Glassprob

Traps Edit

Raiders can pass a trap in two ways: if they win a Sneak vs. Detect roll; or if they fail the Sneak vs. Detect roll, but win a Dodge vs. Snare roll.

This gives a probability of success as:


Advancing and Charging Edit

The probability of success when advancing against a monster is:


The probability of success when charging a monster is the same, except:



Stone Golem Edit

When attacking a stone golem its special ability affects the probabilities:


Fleeing Edit

While there does appear to be a sneak roll in the combat log, whether this roll is won or lost, the monster will go first. Because of this, sneak does not factor in in any way. The probability of successfully fleeing from a monster is:

Fleeprob [1]

Dragon Edit

The slider bar amounts are predictable, for those who care to calculate them. At the far left, zero gold is stolen, and there is a base chance for the dragon to awaken.The basic probability that the Dragon will awaken starts at 10%. Adjusting the starting percentage can happen 3 ways.

  1. Each thief reduces the awakening percent by 2. Four thieves would drop the base 10% by 8, down to 2% chance of awakening the dragon.
  2. Raiding a Dragon of significantly lower renown incurs a penalty increase to the base percent based on the renown relationship. A bigger difference of renown means a bigger penalty.
  3. Repeatedly raiding a Dragon incurs a 25% penalty for each recent success. Succeeding in raiding against this target also resets the timer. Four successful raids against a target would add 100% to the base percent to wake up, an obstacle impossible to surmount with the current units.

Sliding the slider all the way to the right, to its maximum, increases the gold stolen to an amount equal to the raid target's renown. It also increases the chance the dragon will awaken by 90 percent, but there are two things that can modify that.

  1. A thief's abilities would lower the range by 8, so added to their minimum change of 2, they reduce the maximum amount by 10. So in a case with no penalties, base 10% <- range 90% -> maximum 100% with four thieves turns into base 2% <- range 58% -> maximum 60%, quite a reasonable amount. It is important to know the range, as that stays the same, even when the base and maximum percentages change.
  2. The maximum cannot exceed 100%. Any value over 100% is dropped to a ceiling of 100%.

Both the chance of waking the dragon and the gold stolen increase linearly between the minimum and maximum.

All of these adjustments stack, so if one player raided another with a 4% renown penalty that had already been successfully raided once recently, but they brought along 3 thieves, the starting percent would be 33% and the maximum amounts for the slider would be 99% chance of waking the dragon and gold equal to the target's renown.


References Edit

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