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Loot Drop Rate Calculator
Define your own weighted loot table with item names and rarity colours, then read each item's probability, the expected pulls to your first drop, and the chance of at least one in N pulls. Hit simulate to roll a live sample and watch it converge on the theory.
Weights are normalised to 100%. Every pull returns exactly one row, the way a loot table or a single chest slot works.
| x | Percent |
|---|---|
| Gold Coins | 60% |
| Health Poti… | 25% |
| Steel Sword | 10% |
| Enchanted R… | 4% |
| Dragon Blade | 1% |
| Item | Rarity | Weight | Probability |
|---|---|---|---|
| Gold Coins | Common | 60 | 60.0% |
| Health Potion | Common | 25 | 25.0% |
| Steel Sword | Uncommon | 10 | 10.0% |
| Enchanted Ring | Rare | 4 | 4.0% |
| Dragon Blade | Legendary | 1 | 1.0% |
The item name carries its rarity colour, and the rarity word and the number sit beside it, so the odds are clear without relying on colour.
Expected pulls is 1 divided by the drop chance. Even at the expected count, you land it by then only about 63% of the time, so plan for the unlucky runs.
| x | Count |
|---|---|
| Gold Coins | 61 |
| Health Poti… | 27 |
| Steel Sword | 10 |
| Enchanted R… | 0 |
| Dragon Blade | 2 |
| Item | Rolled | Sample % | Theory % |
|---|---|---|---|
| Gold Coins | 61 | 61.0% | 60.0% |
| Health Potion | 27 | 27.0% | 25.0% |
| Steel Sword | 10 | 10.0% | 10.0% |
| Enchanted Ring | 0 | 0.0% | 4.0% |
| Dragon Blade | 2 | 2.0% | 1.0% |
This is one random sample of 100 pulls, so the counts wander around the theory. Roll again to see the variance, or simulate 10,000 to watch the sample settle onto the real percentages.
Copy the table as tab-separated rows for a spreadsheet, copy a plain-text summary for Discord or Reddit, or download a labelled probability card as a PNG.
The math behind a drop rate
A weighted table gives each item a share of the total weight, so an item's probability is its weight divided by the sum of every weight. In the default dungeon chest, the weights add up to 100, which makes the Dragon Blade at weight 1 a clean 1.0% per pull.
- Probability of an item is its weight over the total weight, or, in independent mode, its own percent chance.
- Expected pulls to your first drop is 1 divided by that probability. A 1.0% item takes about 100 pulls on average.
- Chance of at least one in N pulls is 1 minus the chance of missing it every time, which is 1 minus (1 minus p) raised to N. At p = 1.0% and 100 pulls that is 63.4%, not 100%.
Why the expected count is not a promise
Expected pulls is an average, not a guarantee. A drop with a 1% chance takes about 100 pulls on average, but by pull 100 you have only landed it about 63% of the time. Roughly one player in three is still hunting, and about one in a hundred is past 460 pulls. That long tail is what makes a rare drop feel brutal, and it is worth knowing before you write a character grinding the same dungeon for weeks.
The simulate button is there to make the variance real. Roll 100 pulls and the counts jump around. Roll 10,000 and the sample settles onto the theoretical percentages, which is the law of large numbers doing its work.
How to use it
- Build the table by adding a row per drop, giving each a name, a rarity colour, and a weight. Add a Nothing row to model kills that drop nothing.
- Pick how a pull works. Weighted single pick returns one item per pull. Independent chance rolls every row on its own, so a pull can drop several items.
- Read the odds in the probability table, then choose a target item to see the expected pulls to your first one and the chance across N pulls.
- Simulate to roll a live sample, then copy the table or summary, or download the card as a PNG.
Good to know
Questions about this tool
What is the difference between weighted and independent mode?
In weighted mode the weights are normalised to 100% and every pull returns exactly one row, like a single chest slot. In independent mode each row is its own percent chance, so one pull can drop several items and the chances can add past 100%.
What do the expected pulls and the N-pull chance mean?
Pick a target item to see the average number of pulls to its first drop and the chance of at least one in N pulls. At the average, you have the item only about 63% of the time, so plan for unlucky runs.
What does Simulate do?
It rolls a real random sample against your table and tallies the drops beside the theory. Small samples wander, and 10,000 pulls settle close to the exact odds.
How do I add a row that drops nothing?
Give a row the rarity Nothing and a weight. It counts toward the total but carries no rarity colour, so you can model kills that drop no loot.