Weighted Draw Expected Value Calculator Guide
The Weighted Draw Expected Value Calculator computes the EV of any probabilistic draw β gacha pulls, loot boxes, roulettes, raffle drawings β from a list of items with their probabilities and reward values. Use it to compare the long-run statistical value of different draw mechanics or to decide whether a paid draw is worth its cost.
The math is straightforward: EV = Ξ£(probability Γ reward). For example, items at 1%/500, 9%/50, 40%/5, and 50%/0 yield EV = 0.01Γ500 + 0.09Γ50 + 0.4Γ5 + 0.5Γ0 = 11.5. Add as many items as needed using the "Add Item" button.
Enter an optional draw cost (gacha price, ticket fee, etc.) and the tool reports expected profit/loss and ROI. When EV is below cost, the draw is a long-run statistical loss β useful context for buying decisions.
Frequently Asked Questions
Sum (probability Γ reward) for all items.
Ideally yes. A warning appears if they don't.
Yes β include them so probabilities sum to 100% and EV is accurate.