Should you spend on an egg with unknown odds?
If the hatch probability is unknown, you cannot calculate a trustworthy expected value. That does not make spending irrational; it changes the decision from an investment to an entertainment purchase. Decide what the attempt is worth to you before you see the animation, and set a cap that does not depend on the result.
This guide does not tell you which egg to buy. It shows the arithmetic that a probability claim would need and explains why a missing denominator should stay missing. A made-up percentage produces a precise-looking answer that is less honest than 'unknown'.
Three questions before spending
What is the exact cost in your session?
Record the displayed currency and amount, not a remembered price from a video. Include any requirement that must be met before the purchase. If the cost is hidden, stop here.
Is a probability actually displayed?
Look for a number with a denominator or an explicit drop table. A rarity label alone is not a probability. If no number is shown, mark the odds unknown rather than estimating them.
What would the outcome be worth to you?
Write the value in the same unit as the cost. If the outcome is a pet with an unknown income, the value is also unknown. A range with a stated basis is better than a single invented number.
What would expected value require?
Expected value is the probability of the outcome multiplied by its value, minus the cost: EV = p × value − cost. A positive result means the attempt is favourable under those assumptions. A negative result means the cost exceeds the probability-weighted value.
The formula is only as good as its inputs. If p is unknown, the result is unknown. If the outcome has several possibilities, each needs a probability and a value, and the probabilities must sum to a defined pool. A single 'rare' label does not supply that structure.
For illustration only, suppose an egg costs 1,000 and the outcome is worth 50,000. At p = 1%, the expected value is 0.01 × 50,000 − 1,000 = −500. At p = 5%, it is +1,500. The same cost and reward produce opposite conclusions, which is why the missing probability matters.
Break-even probability for hypothetical cost and reward pairs
| Target | Cost | Outcome value | Break-even probability | What it means |
|---|---|---|---|---|
| 1,000 / 50,000 | 1,000 | 50,000 | 2% | A high reward lowers the probability needed |
| 100 / 1,000 | 100 | 1,000 | 10% | Below 10%, the attempt is negative under these values |
| 2,500 / 10,000 | 2,500 | 10,000 | 25% | An expensive attempt needs a common outcome |
| 500 / 5,000 | 500 | 5,000 | 10% | The same ratio, a different scale |
When the odds are unknown
- Set a cap before the attempt and do not raise it after a failure.
- Treat the spend as entertainment rather than an expected return.
- Do not convert a rarity label into a percentage.
- Do not copy a rate from a different egg, event or game.
- Record the result so a future claim has a denominator.
- Keep the attempt separate from a decision that affects your route or pets.
How should a recorded result change the decision?
One result does not establish a probability, but it does establish a denominator for your own record. Ten attempts with one outcome is a 10% observed frequency with a wide uncertainty range, not proof that the game's rate is 10%. Report the count and the conditions, and avoid turning a small sample into a guarantee.
If you later find a displayed probability, compare it with your record only when the pool, event and boost state match. A rate measured under a limited event should not be used to judge an ordinary attempt. The same rule applies to any income or drop claim on this wiki.
Egg budget questions
Can I calculate expected value without odds?
No. Expected value requires a probability for each outcome. Without a displayed or measured probability, the honest result is unknown. You can still set a personal spending cap, but that is a budget decision rather than a calculated return.
Does a rare label mean a low drop rate?
Not necessarily. A label is a category, and the reviewed sources do not attach a probability to it. A low drop rate needs a denominator and a defined pool. Treat the label as identification, not as a number.
Is a small sample enough to estimate odds?
A small sample gives a wide range and can easily mislead. If you record attempts, keep every attempt and report the count. A single success is an anecdote, not an estimate of the game's probability.
Sources and evidence boundaries
- Fake an Egg — official Roblox experience
The public experience description identifies Fake an Egg by Slime Time Studios and its egg-disguise and pet-stealing premise. It does not supply a pet database, current codes, hatch odds, income multipliers or a carrying-speed formula.
Accessed - Fake an Egg — official promotional artwork
The exact experience's official promotional image shows eggs in nests and an avatar inside a cracked egg. It establishes visual identity only, not a controlled real-versus-fake test, animation timing or item stats.
Accessed
