How does the Destiny Knot change the math?

Without it, 3 of the 6 IV slots are inherited from the parents and the rest are random. With it, 5 of the 6 are inherited. More inherited slots means a much higher chance each stat copies a parent's perfect IV.

Why does having two perfect parents help so much?

When a stat slot is inherited, the value is taken from one parent at random. If both parents are perfect in that stat, the inherited value is guaranteed perfect. With one perfect parent it is a coin flip, and with none it can only come from a lucky random roll.

How is the expected number of eggs computed?

The chance of a flawless 6-IV offspring is the product of the per-stat perfect probabilities, since the stats roll independently. The expected number of eggs is one divided by that probability, rounded up.

What does the Everstone do?

An Everstone forces the holding parent's nature onto the offspring 100 percent of the time. Without it, the nature is one random pick out of the natures you specify, which lengthens the grind for a specific nature.

Does this model my exact game?

It implements the widely-used Pokemon-style breeding model with Destiny Knot and Everstone. Games using the same inheritance rules will match closely. If your game differs, treat the numbers as a strong estimate.

CS2 Breeding & IV Calculator

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Plan your breeding grind before you hatch a hundred eggs

Breeding for a flawless offspring is a probability problem, and guessing wastes hours. This CS2 Breeding & IV Calculator applies the real inheritance rules — Destiny Knot, parent copies, random rolls, and nature locking — to tell you the exact odds per stat and how many eggs you should realistically expect.

How it works

Each egg inherits a fixed number of IV slots from the parents — 3 normally, or 5 with a Destiny Knot — and rolls the remaining slots randomly. For a given stat the chance it ends up perfect is:

P(perfect) = (D/6) × (copies/2) + (1 − D/6) × (1 / (maxIV + 1))

where D is the number of inherited slots and copies is how many of the two parents already have a perfect IV in that stat (0, 1 or 2). The first term is the chance the stat is inherited and copies a perfect parent; the second is the chance a random roll happens to land on the maximum value.

Because the six stats roll independently, the chance of a flawless offspring is the product of all six per-stat probabilities. The expected number of eggs to hatch one is the reciprocal of that product.

Tips and example

Two parents that between them cover five perfect IVs, plus a Destiny Knot, make a 6-IV target realistic in a few dozen eggs. Drop to one perfect parent per stat and the expected egg count climbs sharply. Add an Everstone to lock the nature for free; without it, multiply your expected eggs by the number of possible natures to estimate the full grind for a specific nature.