Key
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.