Loot Table Calculator
How many kills does each drop really take?
The weights can be percentages or any numbers. Only how big they are compared with each other matters.
| Item | Chance | Rate | Kills for 50% | for 90% | for 99% | In 50 kills |
|---|---|---|---|---|---|---|
| Common | 70% | 1 in 1.4 | 1 | 2 | 4 | over 99.99% |
| Rare | 25% | 1 in 4 | 3 | 9 | 17 | over 99.99% |
| Epic | 5% | 1 in 20 | 14 | 45 | 90 | 92.3% |
"Kills for 90%" is how many tries it takes before there is a 90% chance of seeing that item at least once.
Ok, I'm building a boss for my game, and the epic drop is 5%. How many kills until a player sees it? Let's work it out.
A player needs about 14 kills for a coin-flip chance. To be 90% sure they need 45 kills, and to be 99% sure they need 90.
So the unlucky player in a hundred is doing the same boss 90 times. I need to decide whether I'm happy with that.
In 50 kills, most people (92%) will have seen one.
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A loot table lists what an enemy or chest can drop and how likely each item is. Enter yours and see, for every item, its chance, how many kills it usually takes and how many it takes to be nearly sure. It helps when you are designing a game, and when you want to know how long a grind will really be.
How it's worked out
- Each weight is divided by the total of all the weights. That is the item's chance.
- Kills for 50%, 90% and 99% are the fewest tries where the chance of seeing the item at least once reaches that level.
- The chance in your number of kills is 1 minus the chance of missing the item every single time.
Weights of 70, 25 and 5 give chances of 70%, 25% and 5%. For the 5% item, 14 kills give a 50% chance, 45 kills give 90% and 90 kills give 99%.
How many tries it takes at common drop rates
| Drop rate | Rate | Tries for 50% | Tries for 90% | Tries for 99% |
|---|---|---|---|---|
| 50% | 1 in 2 | 1 | 4 | 7 |
| 25% | 1 in 4 | 3 | 9 | 17 |
| 10% | 1 in 10 | 7 | 22 | 44 |
| 5% | 1 in 20 | 14 | 45 | 90 |
| 2% | 1 in 50 | 35 | 114 | 228 |
| 1% | 1 in 100 | 69 | 230 | 459 |
| 0.5% | 1 in 200 | 139 | 460 | 919 |
| 0.1% | 1 in 1,000 | 693 | 2,302 | 4,603 |
Tries needed before the chance of seeing at least one drop reaches that level. Each try is separate, and the game has no pity.
Common mistakes
- Designing around the average. If an item is 1 in 20, about half of players need more than 13 kills and one in ten need more than 44. Look at the 90% and 99% columns, because that is what unlucky players feel.
- Checking one item at a time when a player needs several. Needing two different rare items takes much longer than needing one.
- Misreading the weights. 5 out of 100 is 5%, but 5 out of 20 is 25%. Only the total matters, so check the Chance column.
- Forgetting how often the table is rolled. If an enemy rolls it three times, count that as three tries.
Questions
What is the difference between a weight and a percentage?
A percentage is out of 100. A weight can be any number, and an item's chance is its weight divided by all the weights added together. Weights of 70, 25 and 5 and percentages of 70, 25 and 5 give the same answer.
How do I add pity?
This calculator has none, so every roll is separate. For a game with a guaranteed drop after a number of tries, use the Gacha Pull Calculator.
Can I use it for chests, packs and crates?
Yes, for anything where each draw is separate and the odds stay the same. A pack that holds five cards is five draws.
What does the 99% column mean?
It is the number of tries after which there is a 99% chance of having seen the item at least once. About one player in a hundred will still be without it.
Why do the numbers look higher than I expected?
Because the average and the unlucky end are far apart. An item that is 1 in 20 takes 20 tries on average, but one player in ten needs more than 44.
Grinding? Take a quick break.