Calculator · Game design
Egg and drop odds calculator
Put in your egg’s pets and weights. See each chance as a percent and “1 in N”, how many hatches it takes to get one, what luck boosts change, and copy a Luau table with the odds to show players.
Need icons for these pets? Pet Factory makes them with rarity frames and mutations.
Questions
Does Roblox require showing the odds?
Yes. Roblox’s paid random items policy asks you to list every possible outcome with its odds as percentages that add up to exactly 100%, before the purchase, and to show the changed odds when you sell luck boosts. The “Odds to show players” box gives you exactly that, rounded to four decimals.
How does a luck boost work here?
A 2× luck boost multiplies the weights of the chosen rarities and above, then every chance is recalculated so they still add up to 100%. Games implement luck differently; this is the most common way.