Generate weighted loot drop tables with probability calculations. Part of the DevTools Surf developer suite. Browse more tools in the Game Dev collection.
Use Cases
Game designers creating balanced item drop probability tables
RPG developers implementing tiered rarity systems
Mobile game developers designing gacha/loot box distributions
Tabletop RPG dungeon masters generating random treasure tables
Tips
Set rarity weights — common items need much higher weight values
Calculate expected drops per 100 kills for balance verification
Add pity timer mechanics by adjusting weights after N attempts
Fun Facts
Diablo (1996) by Blizzard North popularized randomized loot drops in action RPGs — its loot tables were inspired by roguelike games dating back to Rogue (1980).
The 'pity timer' mechanic, patented by Blizzard in 2016 for Hearthstone card packs, guarantees a rare drop after a certain number of attempts to reduce frustration.
Gacha game loot tables are legally regulated in several countries — Japan's kompu gacha (complete gacha) was banned in 2012, and China requires published drop rates since 2017.
FAQ
How are probabilities weighted?
Relative weights — '5' is 5× more likely than '1'. Total doesn't need to be 100; the tool normalizes.
Can I have nested tables?
Yes — a drop can reference another table. Useful for 'rare drop → pick from rare-item table'.
What formats does it output?
JSON (for custom engines), Unity ScriptableObject boilerplate (C#), or plain text for design docs.
Does it simulate drops?
Yes — roll mode simulates N drops and shows observed frequencies. Useful for verifying rare drops feel rare enough.
