Gacha Pull Probability Calculator

Work out gacha pull probability instantly with clear inputs, formula shown and shareable results.

About Gacha Pull Probability Calculator

Without pity the chance is one minus the miss rate raised to the number of pulls; a hard pity counter guarantees the item once the threshold is reached, capping the worst case. At a 0.6% base rate ninety pulls only gives about a 42% natural chance, so the pity counter rather than the advertised rate is doing most of the work.

Formulas

Base chance

P = 1 - (1 - rate) ^ pulls, capped at the pity threshold

Expected pulls

expected = minimum of pity threshold and 1 / rate

Worked example

With the default values below, Gacha Pull Probability Calculator returns Chance of getting the item of 100.0000%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Base rate per pullaccepts 0–100 %: 0.6 %
Pulls you plan to makeminimum 1: 90
Guaranteed pull atminimum 1: 90
Cost per pullminimum 0.01: 2.2

Results

Chance of getting the item: 100.0000%
Chance from the base rate alone: 41.8199%
Pulls expected before success: 90.00
Expected spend: $198.00

Step by step

1Values used
2Base chance
3Expected pulls
4Chance of getting the item= 100.0000
5Chance from the base rate alone= 41.8199
6Pulls expected before success= 90.00
7Expected spend= 198.00

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Gacha Pull Probability figure worked out?

P = 1 - (1 - rate) ^ pulls, capped at the pity threshold. Without pity the chance is one minus the miss rate raised to the number of pulls; a hard pity counter guarantees the item once the threshold is reached, capping the worst case.

Why does this matter?

At a 0.6% base rate ninety pulls only gives about a 42% natural chance, so the pity counter rather than the advertised rate is doing most of the work.

What do I need to enter?

Enter base rate per pull, pulls you plan to make, guaranteed pull at, cost per pull. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.