So I have heard that you need to include the exact percentages of getting items in your game if you are charging robux for them. I have done this, as I have put the percentage for each rarity in each crate. The problem is that each crate has 2 different items, guns and knives. When a player opens a crate, my system picks a rarity using the percentages and then picks a random item from that rarity. The problem is that the type of item you are getting is random, and no percentage is set for it. Do I have to list the percentage of getting a knife or a gun in each crate along with the rarities, or can I just do rarities?
If all items from the same rarity have an equal chance of being chosen, the percentages of the rarities should be enough.
The thing is I have like 25% of the items are guns and the other 75% are knives average in each crate. I don’t want to go and find the exact percentage, so would be helpful to know this for sure.
You only have to specify the odds of rolling the rarity. You don’t have to specify what the odds are for getting each type of item in that rarity.
Though i wouldn’t recommend using some kind of function to make some items in the same rarity appear more frequently than others. I do not know what the rules on that are.
The regulation was to declare exact percentages. That means if an item of the same rarity but has slightly modified probabilities, has to be declared.
What? So do I have to list item percentages for each crate? I am pretty sure games like mm2 don’t do that.
You don’t have to, for example:
Common: 60%
Rare 30%
Epic: 10%
In this case you don’t have to declare probabilities for each item. That means all common items will have a 60% chance.
Common: 60%
Rare 30%
Epic: Total of 10%
Item 1: 5%
Item 2: 3%
Item 3: 2%
Notice I declared the probability for the epic items since each has a different rate.
If your system only uses a simple rarity system tied to a probability, then you don’t have to declare each individual item. In short, your declaration MUST be accurate and reflects in your code.
As of a recent policy change, if you are able to spend Robux on a crate of chance, you are required to provide the percentages of items that can be obtained from it. This also goes if you use ingame currency to purchase crates but that currency is purchasable with Robux.
The only circumstance in which you are not required to provide percentages for random chance crates or similar is if the crate is obtainable purely from playing the game and the currency used to purchase it does not involve Robux whatsoever, directly or indirectly.
If it’s pure random, it needs to be specified that each item or rarity has an equal chance of being selected and your selection algorithm must reflect that. For weighted randomness, you must include the percentage weightings (percent chance) of receiving each tier.
See the following thread for more information and discussion:
But games like mm2 don’t show the item percentages from each crate, they just show the percentage.
That’s not in violation of the guidelines. In Murder Mystery 2’s case, they have varying tiers of weapons to achieve. Each weapon included in a crate of one rarity has equal chance as another item of the same rarity. Therefore, the item doesn’t need to be shown, just the percentage of each tier.
I strongly encourage you to review the information I’ve given you, as I have already clarified this in that post and provided you the link on Roblox’s stance about this matter. Also avoid using other games as justification or a discussion point for your own case; worry about your own use case and abiding by the rules.
Did the wording of this phrase confuse you? Let me repeat: the use of the word items isn’t limited individually to a single item from a crate. You must list percentages that reflect your algorithm.

If you have a pure random chance of getting something, it needs to be specified that each item has an equal chance of selection (calculate an average percentage for them).

If you have a selection of items that are weighted but have no rarity attached, you need to include the chance of receiving any of those items.

If you have a weighted rarity system where each item of a certain rarity has the same chance of being picked as an item of the same rarity, you need to specify how likely it is to get an item of a certain rarity.
Read the linked thread for more information.
If I have an equal change of getting a gun or knife in each crate, do I have to put 50% and 50% for each crate?
Ideally yes you should be, since those are treated as two different sets of items altogether. It needs to be clear that there’s an equal chance of receiving either a gun or a knife and that one isn’t higher weighted than the other.
The point of the policy is full disclosure about your lootcrate algorithms if real money (thus Robux) is involved in any way directly or indirectly. If the system is based purely on game mechanics, then you do not need to include any kind of percentage disclosure.