💰Gacha Budget Distribution Simulator

Enter your total budget, pull cost, drop rate, and target quantity to see if your budget is enough.

How to Use the Gacha Budget Simulator

Before spending on gacha pulls, find out whether your budget has a realistic chance of hitting your target. Enter your total spending cap, per-pull cost, the item's drop rate, and how many you want — the simulator shows expected drops, success probability, and how much more you'd need on average.

How the Probability Is Calculated

The calculator uses a normal distribution approximation of the binomial distribution. With n pulls at probability p, the mean drops are n×p and the standard deviation is √(n×p×(1−p)). The probability of getting at least your target is derived from this distribution.

Smart Budget Planning

If your success probability is below 50%, reaching your goal is unlikely with this budget alone. Check the "Average Budget Needed" and "Budget Shortfall" fields — they show the statistical minimum spending to average your target, helping you decide whether to save more or lower your expectations.

Frequently Asked Questions

Does 99% probability mean I'm guaranteed to get it?

No — 99% still means a 1% chance of failure. In practice, about 1 in 100 players with that budget won't get the item by luck alone. Keep a small contingency reserve.

My game has a pity system — how does that change things?

Pity guarantees a drop after N pulls, which raises your actual success rate above this calculation. Use this result as a worst-case estimate; your real odds with pity are better.

Is accuracy lower for very rare items?

Yes. The normal approximation is less precise when the rate is below ~0.1% and n is small. For extremely rare items, treat the result as directional guidance rather than an exact number.