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Pet Simulator 99 Hatch Odds Calculator

Pick an egg, enter your hatch count and luck multiplier, and get the exact probability of landing its Secret pet — plus expected hatches for 50% and 90% confidence, a full rarity breakdown, and an expected value per hatch.

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Egg

Chance of at Least One Secret

Effective odds:

Hatch Count

How many eggs you plan to open in this session.

Hatches for 50% Confidence

Luck Boost

Combined luck from gamepasses, potions, and boosts. 1.0 = no boost.

Hatches for 90% Confidence

Quick Load:

Crunching the odds...

Select an egg, enter your hatch count and luck multiplier, then click Calculate Odds to see the full breakdown.

How Hatch Probability Climbs With More Eggs

A 1-in-3,000,000 Secret doesn't mean you need exactly 3,000,000 hatches — probability compounds with every egg you open. The chart below shows cumulative probability at increasing hatch milestones for a 1-in-3,000,000 Secret with no luck boost:

Formula: probability of at least one hit = 1 − (1 − p)^hatches, where p is the per-hatch odds. Notice the curve rises fast early on and flattens later — going from 3M to 5M hatches (a 67% increase in eggs) only adds about 18 percentage points, since you're increasingly likely to have already hatched it by then.

FactorFormula
Effective OddsBase Odds (1 ÷ Denominator) × Luck Multiplier, capped at 100%
Probability of At Least One1 − (1 − Effective Odds)^Hatches
Hatches for X% Confidenceln(1 − X) ÷ ln(1 − Effective Odds)
Expected Value Per HatchEffective Odds × Secret Pet's Estimated Value

The Six Rarity Tiers

Every egg follows the same rarity structure — five fixed common-to-legendary tiers, plus a Secret tier whose odds vary by egg.

RarityTypical Odds
Common55%
Unique25%
Rare12%
Epic6%
Legendary~2% (egg-dependent)
Secret1 in 2,200,000 to 1 in 5,000,000 (egg-dependent)

Luck Tier Reference

Your results carry one luck tier badge, classified by the luck multiplier you entered.

Luck MultiplierTier
1.0x (none)No Boost
1.01x – 2.99xLucky
3.00x – 9.99xVery Lucky
10.0x+Blessed

Frequently Asked Questions

How many hatches does it take to get a Secret pet?
It depends on the egg's Secret odds and your luck multiplier. With no luck boost, a 1-in-3,000,000 Secret needs roughly 2.08 million hatches for a 50% chance and about 6.9 million hatches for a 90% chance. A luck boost of 5x or 10x cuts those numbers dramatically — enter your own multiplier above for an exact figure.
What does a luck multiplier actually do?
It multiplies your effective odds of hatching the Secret pet directly — a 2x luck multiplier roughly doubles your chance per hatch, which in turn roughly halves the number of hatches needed to reach any given confidence level. Luck stacks from gamepasses, potions, and event boosts.
Are these odds official Pet Simulator 99 drop rates?
No. Big Games hasn't published an official drop-rate table, so the figures here are illustrative, community-tested estimates gathered from large-scale player hatch tracking — not a guaranteed live feed. Rates can shift between game updates, so treat your result as a realistic estimate rather than a certainty.
What is "expected value per hatch" and why does it matter?
It's your Secret pet's odds multiplied by its estimated value — a rough long-run average of how much "value" one hatch is worth from the Secret alone. It's typically a small fraction of a cent per hatch, since Secrets are rare, but it's a useful way to compare whether grinding one egg over another is more worthwhile per hatch.
Why is the 90% confidence number so much higher than the 50% number?
Probability curves flatten out the closer they get to 100% — closing the remaining gap takes disproportionately more hatches. Going from 50% to 90% confidence typically requires more than triple the hatches, not just 1.8x, because you're squeezing out an increasingly unlikely "still hasn't happened yet" scenario.
Is this the same as the Gacha Pity or Pulls to Pity calculators on this site?
No. Gacha games like Genshin Impact and Honkai: Star Rail guarantee a rare unit after a fixed "hard pity" number of pulls, which is a completely different (deterministic-ceiling) system. Pet Simulator 99 has no pity mechanic — every hatch is an independent probability roll, so this calculator uses pure probability math instead of a pity-counter model.
What's the hardest Secret pet to hatch in this calculator?
The Golden Griffin from the Golden Egg, at roughly 1-in-5,000,000 base odds — also the highest estimated value in the catalogue at $35, reflecting just how rare a genuine unboosted pull is.

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External Resources

Pet Simulator 99 Wiki — eggs, worlds, and pet details Pet Simulator 99 on Roblox — official game page