What is a relative weight?

A weight is any positive number that represents how likely an item is to drop compared to others. Only the ratios matter — weights of 1, 2, 1 give the same rates as 10, 20, 10. The tool normalizes them to percentages automatically.

How accurate is the simulation?

The simulation uses JavaScript's Math.random(), a cryptographically non-uniform but statistically adequate PRNG. At high roll counts (100k+) simulated rates converge within fractions of a percent of theoretical values.

Why do simulated rates differ from expected rates?

Random variance — the same reason a fair coin sometimes shows 6 heads in 10 flips. The higher the roll count, the closer simulated rates converge to expected rates. Large deviations at low counts are normal.

Can I have more than one item with the same name?

Duplicate names are allowed — each row is treated as an independent entry. This is useful when you want a single item to have multiple weight contributions (e.g. tiered variants).

Is there a limit on the number of items?

The tool supports up to 50 items. Most real loot tables have far fewer.

What happens if I set a weight of zero?

Items with zero weight are excluded from the probability calculation and simulation. They appear in the table with 0% drop chance.

Loot Table Balancer

Name: Loot Table Balancer
Availability: InStock
Author: Nham Vu

Define loot items with relative weights, see exact drop percentages, and run a simulation to validate your table balance.

Loot Items

Simulation

Number of Rolls

Drop Rates

Total weight: 0

Add items on the left to see drop rates

Item	Weight	Expected %	Sim Rolls	Sim %	Diff

Probability Distribution

Summary

Define loot items with relative weights, see exact drop percentages, and run a simulation to validate your table balance.

How it works

Add each item you want in the loot pool along with its relative weight (any positive number).
The tool normalizes all weights and shows each item's exact drop probability as a percentage.
Set the number of rolls you want to simulate (1 to 1,000,000).
Click "Simulate Rolls" to run a pseudo-random draw for every roll using your weighted table.
The results table shows simulated count, simulated rate, and the difference from the expected rate.

Use cases

Balance a chest loot pool before shipping a game update.
Verify that rare items are rare enough and common items are common enough.
Compare multiple weight configurations side by side to find the best feel.
Estimate how many runs a player needs to see a specific item at least once.
Design gacha or card-pack pull rates and validate them against regulations.
Debug unexpected drop distributions in an existing live game table.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu