RuneScape Wiki
This article has a calculator here.
Calculators determine experience and costs based on real-time prices from the Grand Exchange Market Watch.
Debilitate deals no damage but gains up to 6% per rank extra duration from shield value.
Release date 25 January 2016 (Update)
Gizmo type Armour
Maximum rank 3

Bulwark is an Invention perk that lengthens the duration of Debilitate but decreases all damage it deals to 0. It can be created in armour gizmos.

Bulwark's extra duration seems to be a minimum of +1 game tick per rank. The only shield tier where the increase in duration is larger than +1 per rank is tier 90 (and only for rank 3). This does then mean that using debilitate without a shield will still see an increase in duration from the Bulwark perk for all ranks.

Bulwark increases Debilitate's uptime by 2.4 seconds out of 30 if used with a tier 90 shield. This is a 17.3% increase, resulting in 8.65% overall increased damage reduction provided the player uses the ability every 30 seconds when it comes off cooldown, has 100% hit chance, is fighting against one opponent, and damage taken is not classified as hard typeless.


  • The length of time (in game ticks) that Debilitate lasts with the Bulwark perk, , is
  • is the rank of the Bulwark perk.
  • is the length of time, measured in game ticks, that Debilitate would last if the Bulwark perk were not used. This value does include the tier of shield being used.

This is a dynamic calculator that requires Javascript.
This takes user input via Javascript, and may use changing prices from the Grand Exchange Market Watch.
If prices appear to be outdated, purge the page by clicking here.
 template  = Calculator:Bulwark/template
 form      = exprCalcForm
 result    = exprCalcResult
 param     = shieldTier|Shield Tier|90|int|0-99

This text will disappear if the form is loaded properly.
This text will disappear if the form is submitted.
  • The same calculator along with documentation can be found at the top of this page.
Debilitate length
Rank Increase Time
Minimum[1] Maximum[2]
None 0% 7.8s 13.8s
1 6% 8.4s 14.4s
2 12% 9.0s 15.0s
3 18% 9.6s 16.2s
  1. ^ As calculated with no shield equipped
  2. ^ As calculated with a tier 90 shield equipped


MaterialRarityPerk ranks with X materials
Resilient components.png
Resilient componentsRare01223
Cover parts.png
Cover partsCommon011–21–21–2
Powerful components.png
Powerful componentsUncommon011–21–21–3
Heavy components.png
Heavy componentsUncommon011–21–21–3
Metallic parts.png
Metallic partsCommon011–21–21–2

Suggested gizmos

Gizmo layout Possible perks
Resilient components.png
Resilient components.pngResilient components.pngResilient components.png
Resilient components.png
  • Bulwark.png Bulwark 3
Resilient components.png
Resilient components.pngResilient components.pngEvasive components.png
Evasive components.png
  • Other possible perks: