Preservation Chance

Preservation Chance is a modifier which allows resources to be preserved when creating items, allowing for the creation of items at no cost to the player. When resource preservation triggers, the player will receive a notification stating "You managed to preserve your resources".

This page is up to date (v1.2.2).

The chance to preserve resources only applies when creating items within a skill, it does not affect:

• Potion dose preservation
• Summoning tablet preservation
• Prayer point preservation
• Rune Preservation in Magic
• Ammo Preservation in Ranged
• Dig site map excavation preservation in Archaeology

The preservation chance for all skills is capped at 80%, unless a modifier which increases the cap applies.

Like preservation, doubling helps create more output for the same input. But doubling does this by increasing the output for each action taken, while preservation increases the number of actions possible for each unit of input. For sources of doubling, see Skill Boosts#Doubling Boosts for global modifiers or the "Skill Boosts" section of a specific skill. See Double Loot for more about doubling in combat.

Sources

Below is a list of many things other than Mastery bonuses and Summoning synergies which provide a chance to preserve resources. Another notable mention is that the Crown of Rhaelyx gains 15% preservation chance (for a total of 25%) when the player has at least one Charge Stone of Rhaelyx within their Bank.

Source	Type	Preservation Bonuses	Other Modifiers
Pipe Balance	Agility Obstacle 3	+3% Chance to Preserve Resources in Skills	+3% Chance to deal no Damage to an Ore or Essence Mining Node +10 Mining Node Hitpoints
Coal Stones	Agility Obstacle 4	+3% Chance to Preserve Resources in Skills	-4% Global Skill XP +10% Food Healing Value +20% GP From Thieving
Mud Crawl	Agility Obstacle 4	+3% Chance to Preserve Resources in Herblore	-10% Farming Yield +2% Herblore Mastery XP +2% Herblore Skill XP
Rock Climb	Agility Obstacle 5	-10% Chance to Preserve Resources in Skills	+5% Chance to Double Items in Fishing +5% Chance to Double Items in Woodcutting +5% Chance to Double Items in Mining +5% Chance to Double Items in Thieving
Tree Climb	Agility Obstacle 5	-10% Chance to Preserve Resources in Skills	-10% Ammo Preservation -10% Rune Preservation +3% Global Mastery XP +4% Global Skill XP
Tree Hop	Agility Obstacle 6	+5% Chance to Preserve Resources in Skills	+5% Ammo Preservation +5% Rune Preservation
Boulder Trap	Agility Obstacle 7	-20% Chance to Preserve Resources in Skills
Runic Trail	Agility Obstacle 8	-16% Chance to Preserve Resources in Herblore +5% Chance to Preserve Resources in Summoning	+15% Chance to preserve Summoning Charges +3 Base Quantity for Summoning Tablet Creation
Sweltering Pools	Agility Obstacle 8	-20% Chance to Preserve Resources in Skills	-3% Cooking Interval +10% Auto Eat Efficiency +10% Food Healing Value +3% Cooking Mastery XP
Ice Jump	Agility Obstacle 9	+10% Chance to Preserve Resources in Skills	+5% Chance to Double Items Globally +20 Maximum Hitpoints +5% Food Healing Value +10 Mining Node Hitpoints
Lava Waterfall Dodge	Agility Obstacle 10	+10% Chance to Preserve Resources in Skills	+5% Ammo Preservation +10% Chance To Preserve Prayer Points +10% Rune Preservation
Pit Maze	Agility Obstacle 11	-20% Chance to Preserve Resources in Skills	+2% chance to receive a Quality Superior Gem while Mining Gem Veins or Meteorite Ore +3% Global Mastery XP +15 Mining Node Hitpoints
Cave Waters	Agility Obstacle 12	-10% Chance to Preserve Resources in Herblore	-6% Global Mastery XP +15% Chance To Preserve Potion Charge
Monkey Trail	Agility Obstacle 12	-10% Chance to Preserve Resources in Skills	-5% Cooking Interval -6% Agility Skill XP +15% Farming Yield +10% Food Healing Value
Cave Trap	Agility Obstacle 13	-10% Chance to Preserve Resources in Skills	-50 Maximum Hitpoints +5% Chance To Preserve Potion Charge +5% Chance to preserve Summoning Charges
Lava Trail	Agility Obstacle 15	+15% Chance to Preserve Resources in Skills	-8% Global Mastery XP
Mountain Trail	Agility Obstacle 15	-20% Chance to Preserve Resources in Skills	-0.2s Smithing Interval -0.2s Fletching Interval -0.2s Crafting Interval +30% Chance to gain +1 additional resource in Smithing (Cannot be doubled) +30% Chance to gain +1 additional resource in Fletching (Cannot be doubled) +30% Chance to gain +1 additional resource in Crafting (Cannot be doubled) +3% chance to receive a Quality Superior Gem while Mining Gem Veins or Meteorite Ore
Pillar of Skilling	Agility Pillar	+3% Chance to Preserve Resources in Skills	+3% Chance to Double Items Globally +10% Farming Yield +2% Global Mastery XP
Bear	Item (Summon1, Summon2)	+5% Chance to Preserve Resources in Herblore
Candelabra (Lit)	Item (Consumable)	+3% Chance to Preserve Resources in Skills	-3% Interval for all non-Combat Skills +4% Global Mastery XP +4% non-Combat Skill XP
Cape of Completion	Item (Cape)	+20% Chance to Preserve Resources in Summoning	Bypass Slayer Area item requirements for areas that require less than level 100 Slayer -20% Agility Obstacle Build Costs -50% Prayer Point Cost for Prayers (Prayer Point cost cannot go below 1) -0.5s Thieving Interval -0.5s Crafting Interval -15% Woodcutting Interval -15% Cooking Interval -50% Coal Costs for Smithing -15% Township Building Cost (Does not affect GP cost. Capped at -80%) x2 Items received from Fishing x2 Items received from Fletching x2 Items received from Herblore Create +5 Additional Runes of the same type in Runecrafting +50% Ammo Preservation +1 to base drop quantity of Stardust and Golden Stardust from Astrology +1 Coal Ore per Ore Mined. (Item doubling does not apply) +100% chance to receive Ash per log burnt in Firemaking +2% Global Perfect Cook chance +100% chance to successfully Cook an item +15% Chance to Double Items in Runecrafting +5% Damage To Slayer Tasks +25% Farming Yield +100% chance to receive coal when burning logs in Firemaking +10% GP From Agility +100% GP From Thieving +5% Global Skill XP +10 Flat Hitpoints Regeneration +25% Mastery Pool XP Cap Items that reduce Rune costs are now 2x as effective +25% Flat Slayer Area Effect Negation +10% Chance to preserve Summoning Charges +10 Base Quantity for Summoning Tablet Creation +150 Stealth while Thieving
Cape of Completion (Atlas of Discovery)	Item (Cape)	+20% Chance to Preserve Resources in Cartography	-20% dig site map refinement cost -50% Cartography Dig Site Map upgrade interval -30% Cartography survey interval +3 levels of the Brush Tool in Archaeology +15% chance to preserve dig site map excavation actions +1 minimum Items found in Archaeology +3 levels of the Shovel Tool in Archaeology +3 levels of the Sieve Tool in Archaeology +3 levels of the Trowel Tool in Archaeology
Cartography Skillcape	Item (Cape)	+10% Chance to Preserve Resources in Cartography	-10% dig site map refinement cost -20% Cartography Dig Site Map upgrade interval
Chefs Bag	Item (Consumable)	+10% Chance to Preserve Resources in Cooking	+20% Chance to Double Items in Cooking
Clown Hat	Item (Helmet)	-10% Chance to Preserve Resources in Skills	-5% Global Skill XP +10% Global Mastery XP
Crown of Rhaelyx	Item (Helmet)	+10% Chance to Preserve Resources in Skills
Maximum Skillcape	Item (Cape)	+20% Chance to Preserve Resources in Summoning	Bypass Slayer Area item requirements for areas that require less than level 100 Slayer -20% Agility Obstacle Build Costs -50% Prayer Point Cost for Prayers (Prayer Point cost cannot go below 1) -0.5s Thieving Interval -0.5s Crafting Interval -15% Woodcutting Interval -15% Cooking Interval -50% Coal Costs for Smithing -15% Township Building Cost (Does not affect GP cost. Capped at -80%) x2 Items received from Fishing x2 Items received from Fletching x2 Items received from Herblore Create +5 Additional Runes of the same type in Runecrafting +50% Ammo Preservation +1 to base drop quantity of Stardust and Golden Stardust from Astrology +1 Coal Ore per Ore Mined. (Item doubling does not apply) +100% chance to receive Ash per log burnt in Firemaking +2% Global Perfect Cook chance +100% chance to successfully Cook an item +15% Chance to Double Items in Runecrafting +5% Damage To Slayer Tasks +25% Farming Yield +100% chance to receive coal when burning logs in Firemaking +10% GP From Agility +100% GP From Thieving +5% Global Skill XP +10 Flat Hitpoints Regeneration Items that reduce Rune costs are now 2x as effective +25% Flat Slayer Area Effect Negation +10% Chance to preserve Summoning Charges +10 Base Quantity for Summoning Tablet Creation +150 Stealth while Thieving
Peasant Shirt	Item (Platebody)	+8% Chance to Preserve Resources in Skills	-30% Global GP (except Item Sales)
Pig	Item (Summon1, Summon2)	+10% Chance to Preserve Resources in Cooking
Ring of Wealth	Item (Ring, Passive)	-3% Chance to Preserve Resources in Skills	+7% Chance to Double Items Globally
Salamander	Item (Summon1, Summon2)	+5% Chance to Preserve Resources in Smithing
Sturdy Fancy Quill	Item (Weapon)	+20% Chance to Preserve Resources in Cartography	-5% Cartography Interval +20% Chance to Double Items in Cartography +8% Cartography Skill XP
Summoning Scrolls	Item (Consumable)	+10% Chance to Preserve Resources in Summoning	+10% Chance to preserve Summoning Charges +15 Base Quantity for Summoning Tablet Creation
Summoning Skillcape	Item (Cape)	+20% Chance to Preserve Resources in Summoning	+10% Chance to preserve Summoning Charges +10 Base Quantity for Summoning Tablet Creation
Superior Cape of Completion	Item (Cape)	+25% Chance to Preserve Resources in Summoning	Bypass All Slayer Area item requirements -30% Agility Obstacle Build Costs -20% Agility Pillar build costs -75% Prayer Point Cost for Prayers (Prayer Point cost cannot go below 1) -0.8s Thieving Interval -0.8s Crafting Interval -20% Woodcutting Interval -25% Cooking Interval -10% Summoning Interval -10% Astrology Interval -75% Coal Costs for Smithing -20% Township Building Cost (Does not affect GP cost. Capped at -80%) x2 Items received from Fishing x2 Items received from Fletching x2 Items received from Herblore Create +8 Additional Runes of the same type in Runecrafting +75% Ammo Preservation +2 to base drop quantity of Stardust and Golden Stardust from Astrology +1 Bolts produced per action in Fletching +2 Coal Ore per Ore Mined. (Item doubling does not apply) +50% Chance to gain +1 additional bar in Smithing (Cannot be doubled) +100% Chance to gain +1 additional resource in Fishing (Cannot be doubled) +100% Chance to gain +1 additional resource in Fletching (Cannot be doubled) +15% Chance to gain +1 additional resource in Crafting (Cannot be doubled) +100% Chance to gain +1 additional resource in Herblore (Cannot be doubled) +20% Chance to Double Farming Yield +100% chance to receive Ash per log burnt in Firemaking +100% chance to receive Charcoal per burn in Firemaking +4% Global Perfect Cook chance +100% chance to successfully Cook an item +20% chance to avoid the stun interval and stun damage in Thieving when pickpocket attempt fails +25% Chance to Double Items in Runecrafting +1% chance to find a Lost Chest while Fishing (This is separate to the Special Fishing Chance) +5% Chance to Preserve Food when eaten +5% Chance To Preserve Potion Charge +5% Chance To Preserve Prayer Points +8% Damage To Slayer Tasks +40% Farming Yield +100% chance to receive coal when burning logs in Firemaking +20% GP From Agility +150% GP From Thieving +5% Chance to find gem veins when Mining +8% Global Skill XP +15 Flat Hitpoints Regeneration +5% Lifesteal +5% Magic Damage Bonus from Equipment +5% Melee Strength Bonus from Equipment +1 minimum Bird Nest's received from Woodcutting +5% of Maximum Hit added to Minimum Hit +5% Ranged Strength Bonus from Equipment +5% Reflect Damage +10% Rune Preservation Items that reduce Rune costs are now 4x as effective +35% Flat Slayer Area Effect Negation +10% Slayer Coins +15% Chance to preserve Summoning Charges +10 Base Quantity for Summoning Tablet Creation +10% Summoning Maximum Hit +270 Stealth while Thieving
Superior Cartography Skillcape	Item (Cape)	+20% Chance to Preserve Resources in Cartography	-20% dig site map refinement cost -50% Cartography Dig Site Map upgrade interval -30% Cartography survey interval
Superior Max Skillcape	Item (Cape)	+25% Chance to Preserve Resources in Summoning	Bypass All Slayer Area item requirements -30% Agility Obstacle Build Costs -20% Agility Pillar build costs -75% Prayer Point Cost for Prayers (Prayer Point cost cannot go below 1) -0.8s Thieving Interval -0.8s Crafting Interval -20% Woodcutting Interval -25% Cooking Interval -10% Summoning Interval -10% Astrology Interval -75% Coal Costs for Smithing -20% Township Building Cost (Does not affect GP cost. Capped at -80%) x2 Items received from Fishing x2 Items received from Fletching x2 Items received from Herblore Create +8 Additional Runes of the same type in Runecrafting +75% Ammo Preservation +2 to base drop quantity of Stardust and Golden Stardust from Astrology +1 Bolts produced per action in Fletching +2 Coal Ore per Ore Mined. (Item doubling does not apply) +50% Chance to gain +1 additional bar in Smithing (Cannot be doubled) +100% Chance to gain +1 additional resource in Fishing (Cannot be doubled) +100% Chance to gain +1 additional resource in Fletching (Cannot be doubled) +15% Chance to gain +1 additional resource in Crafting (Cannot be doubled) +100% Chance to gain +1 additional resource in Herblore (Cannot be doubled) +20% Chance to Double Farming Yield +100% chance to receive Ash per log burnt in Firemaking +100% chance to receive Charcoal per burn in Firemaking +4% Global Perfect Cook chance +100% chance to successfully Cook an item +20% chance to avoid the stun interval and stun damage in Thieving when pickpocket attempt fails +25% Chance to Double Items in Runecrafting +1% chance to find a Lost Chest while Fishing (This is separate to the Special Fishing Chance) +5% Chance to Preserve Food when eaten +5% Chance To Preserve Potion Charge +5% Chance To Preserve Prayer Points +8% Damage To Slayer Tasks +40% Farming Yield +100% chance to receive coal when burning logs in Firemaking +20% GP From Agility +150% GP From Thieving +5% Chance to find gem veins when Mining +8% Global Skill XP +15 Flat Hitpoints Regeneration +5% Lifesteal +5% Magic Damage Bonus from Equipment +5% Melee Strength Bonus from Equipment +1 minimum Bird Nest's received from Woodcutting +5% of Maximum Hit added to Minimum Hit +5% Ranged Strength Bonus from Equipment +5% Reflect Damage +10% Rune Preservation Items that reduce Rune costs are now 4x as effective +35% Flat Slayer Area Effect Negation +10% Slayer Coins +15% Chance to preserve Summoning Charges +10 Base Quantity for Summoning Tablet Creation +10% Summoning Maximum Hit +270 Stealth while Thieving
Superior Summoning Skillcape	Item (Cape)	+25% Chance to Preserve Resources in Summoning	-10% Summoning Interval +15% Chance to preserve Summoning Charges +10 Base Quantity for Summoning Tablet Creation +10% Summoning Maximum Hit
Gunter	Pet	+10% Chance to Preserve Resources in Runecrafting
Puff, the Baby Dragon	Pet	+10% Chance to Preserve Resources in Smithing
The Monolith	Point of Interest	+5% Chance to Preserve Resources in Cartography	-5% Cartography Dig Site Map upgrade interval +5% chance to preserve dig site map excavation actions

Chance Cap

The preservation chance for all skills is capped at 80%. For a few skills, there exists bonuses which can increase this cap:

• The Bear & Beaver synergy can increase the cap for Fletching by 5%
• The Bear & Fox synergy can increase the cap for Herblore by 5%
• The Herblore Preservation Scroll from Township can increase the cap for Herblore by 5%. This stacks with the above.

Calculating Gains

Let's say you have 120 bars, 80% resource preservation, and 0% doubling chance. If a dagger takes one bar to create, how many daggers would you create on average out of 120 bars?

The answer is [math]\displaystyle{ \frac{120}{1 - 80/100} = \frac{120}{0.2} = 600. }[/math]

The main idea behind resource preservation is that you can reuse the preserved resources to make more items, but those resources when used will themselves be preserved also.

Using the same example with 120 bars, you take 120 actions producing 120 daggers, but with 80% preservation you are left with [math]\displaystyle{ 120 \times 0.8 = 96 }[/math] bars.

Now you can use those 96 bars to do the same thing, and you will be left with [math]\displaystyle{ 96 \times 0.8 = 76.8 }[/math] bars on average.

Repeat that to infinity, and you will get the average number of daggers that you will produce from 120 bars.

But how do we calculate this number?

So the number of daggers produced is [math]\displaystyle{ 120 + (120 \times 0.8) + (120 \times 0.8 \times 0.8) +\cdots + (120 \times 0.8^n) }[/math] where [math]\displaystyle{ n }[/math] goes to infinity.

If we generalize and represent the number of starting resources ([math]\displaystyle{ 120 }[/math]) with [math]\displaystyle{ a }[/math] and the probability ([math]\displaystyle{ 0.8 }[/math]) with [math]\displaystyle{ r }[/math], the number of actions performed with [math]\displaystyle{ a }[/math] action's worth of starting resources and a resource preservation of [math]\displaystyle{ r }[/math] (where [math]\displaystyle{ 0 \le r \lt 1 }[/math]) can be expressed as follows:

[math]\displaystyle{ a + (a \times r) + (a \times r \times r) + \cdots + (a \times r^n) = \sum\limits^{\infty}_{n=0} ar^n }[/math]

This expression is an infinite geometric series, which can simply be expressed as [math]\displaystyle{ \displaystyle \lim_{n \to \infty}\tfrac{a(1 - r^n)}{1 - r} = \frac{a}{1 - r} }[/math].

So, coming back to our example where [math]\displaystyle{ a = 120 }[/math] and [math]\displaystyle{ r = 0.8 }[/math], we get [math]\displaystyle{ \frac{120}{1 - 0.8} = 600 }[/math].

Melvor Idle version v1.2.2 (Released: 15th November 2023)
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