Key: Difference between revisions

Key
	Key
Rarity	Common
Type	Item
Effect	+10% chance to open chests for free.

VisualWikitext

Latest revision as of 16:25, 17 November 2025

Key is a Common Item in Megabonk. It gives a 9.1% chance for chests to open without consuming gold. If a chest is opened for free, the price of opening another chest will not increase.

The chance to open the chest for free is rolled after receiving the item inside, meaning you can open a chest for free even if that chest gave you your first key.

How to Unlock

Purchase items from 25 chests.

How Keys Stack

Formula used in Megabonk for calculating free chest chance:

freeChestChance = totalKeyChance / (totalKeyChance + 1)

For example: Free chest chance with 3 keys:

freeChestChance = 0.3 / (0.3 + 1) * 1 ≈ 0.2307


Keys	% Chance For Free Chest	% Chance Increase	Expected Chests Per Free
1	9.10%		11
2	16.70%	7.60%	6
3	23.10%	6.40%	4.3
4	28.60%	5.50%	3.5
5	33.30%	4.80%	3
6	37.50%	4.20%	2.7
7	41.20%	3.70%	2.4
8	44.40%	3.30%	2.2
9	47.40%	2.90%	2.1
10	50.00%	2.60%	2

This graph uses a simplified formula "n/(n+10)" which gives the same results as "n/(n+1)" or "n/(n+1)*1" however n = the number of keys instead of the percentage chance of all keys added together.

- NOTE: These values may not match up with the ingame item description but they have been verified via datamining & in-game testing.

Strategy & Synergies

Enables getting more items than would typically be possible in a single run. When paired with the Golden Shield + Kevin combo for gold generation, this can massively increase the amount of items obtained before the 3rd stage boss fight.
Stacking Keys with the Credit Card (Green) is an optimal strategy for getting a very high Luck stat in high score runs without relying on the Luck Tome or Fox's passive. However, this strategy will require a lot of resetting to get a good run started.
Credit Card (Red) also synergizes well with keys, though it is far less impactful than the two synergies listed above due to poor damage scaling with other items.
Luck does not affect the chance for Key to trigger.

@@ Line 6: / Line 6: @@
 | effect   = +10% chance to open chests for free.
 }}
-'''Key''' is a Common [[Items|Item]] in '''Megabonk'''. It is an economy-focused item that gives a '''+10% chance to open chests for free'''.
+'''Key''' is a Common [[Items|Item]] in '''Megabonk'''.
+It gives a 9.1% chance for chests to open without consuming gold. If a chest is opened for free, the price of opening another chest will not increase.
+The chance to open the chest for free is rolled ''after'' receiving the item inside, meaning you can open a chest for free even if that chest gave you your first key.
 == How to Unlock ==
-To unlock the Key item, the player must '''purchase items from 25 chests'''.
+Purchase items from 25 chests.
+== How Keys Stack ==
+Formula used in ''Megabonk'' for calculating free chest chance:
+<code>freeChestChance = totalKeyChance / (totalKeyChance + 1)</code>
+'''For example:''' Free chest chance with 3 keys:
+<code>freeChestChance = 0.3 / (0.3 + 1) * 1 ≈ 0.2307</code>
+{| class="wikitable"
+|+
+!Keys
+!% Chance For Free Chest
+!% Chance Increase
+!Expected Chests Per Free
+|-
+|1
+|9.10%
+|
+|11
+|-
+|2
+|16.70%
+|7.60%
+|6
+|-
+|3
+|23.10%
+|6.40%
+|4.3
+|-
+|4
+|28.60%
+|5.50%
+|3.5
+|-
+|5
+|33.30%
+|4.80%
+|3
+|-
+|6
+|37.50%
+|4.20%
+|2.7
+|-
+|7
+|41.20%
+|3.70%
+|2.4
+|-
+|8
+|44.40%
+|3.30%
+|2.2
+|-
+|9
+|47.40%
+|2.90%
+|2.1
+|-
+|10
+|50.00%
+|2.60%
+|2
+|}
+[[File:PercForFreeChest.png|frameless|upright=1.85|Chance of getting a free chest from 0 to 30 keys.]]
+''This graph uses a simplified formula "n/(n+10)" which gives the same results as "n/(n+1)" or "n/(n+1)*1" however n = the number of keys instead of the percentage chance of all keys added together.''
+- NOTE: These values may not match up with the ingame item description but they have been verified via datamining & in-game testing.
 == Strategy & Synergies ==
-The Key is an economy item that can save a significant amount of gold over the course of a long run, allowing you to purchase more items.
+* Enables getting more items than would typically be possible in a single run. When paired with the [[Golden Shield]] + [[Kevin]] combo for gold generation, this can massively increase the amount of items obtained before the 3rd stage boss fight.
-* Its value is based on luck, but on average, it will open 1 out of every 10 chests for free.
+* Stacking Keys with the [[Credit Card Green|Credit Card (Green)]] is an optimal strategy for getting a very high Luck stat in high score runs without relying on the [[Luck Tome]] or [[Fox]]'s passive. However, this strategy will require a lot of resetting to get a good run started.
-* The gold saved can be used for other upgrades, making it a solid investment if found early.
+* [[Credit Card Red|Credit Card (Red)]] also synergizes well with keys, though it is far less impactful than the two synergies listed above due to poor damage scaling with other items.
-* The unlock condition rewards players for actively engaging with the chest mechanic.
+* Luck does not affect the chance for Key to trigger.
 [[Category:Items]]
 {{#seo:
-|description=In Megabonk, the Key is a Common item giving a +10% chance to open chests for free. This guide covers its unlock condition and its utility for in-run economy.
+|description=Key adds a 10% chance to open chests for free. Unlock after buying from 25 chests.
 |image=Item_Key.png
 |image_alt=Key item icon in Megabonk.
 }}