Roll Cost & Probability Calculator

Estimate roll counts, rarity probabilities, expected pulls, and currency burn with transparent community-estimate inputs.

Enter your values to compare scenarios; the calculation runs only in this browser.

Interactive island · Preact

Route income calculator

Compare fictional route rewards with transparent, tested arithmetic.

Chance of at least one target33.52%Expected target pulls0.4

Cost to chance thresholds: 50% 1,700 · 90% 5,700 · 99% 11,300

Leftover currency: 0

This calculator treats each roll as an independent Bernoulli trial. The rarity defaults are community estimates, not an official drop table, so replace them with your own observed values when you have better evidence.

How the model works

Affordable rolls are floor(currency / cost per roll), with the remainder shown rather than silently spent. For a target probability p across n rolls, the chance of at least one target is 1 - (1 - p)^n; expected pulls are n × p and variance is n × p × (1 - p).

The browser caps scenarios at 10,000 rolls. A hard-pity counter can force the displayed next-roll chance to 100% when the counter reaches the supplied threshold. This is a planning assumption and should be checked against the current client.

Reading the outputs

Use the 50%, 90%, and 99% currency thresholds to compare a target rarity with your actual budget. A 0.05% Diamond estimate at one roll is 0.05%, or approximately one in 2,000 under that assumption; it is not a promise that every 2,000 rolls contains a Diamond.

Limitations

The Standard, Event, and Crossover presets are editable scenarios. They do not prove a banner’s live rates, pity carry-over, or independence. See the Roll Cost and Probability article for source notes.