Choose two to four pets, set the mutation and weight ratio of the copies you actually have, and the table shows them side by side: rarity, where each one comes from, the Speed you need to reach its nest, and $/s per second, hour and day. Under the table, a swap check tells you how much income you gain or lose by putting one pet in a pen slot in place of the first one.
The swap check compares income only. It is not a trade value: what other players will give you for a pet depends on demand and scarcity, which no public data tracks. Weight ratio = hatched weight / base weight (1 = normal). Luminous Reroll and Zombified pets are separate entries in the pet list, so pick them directly rather than adding a mutation.
How the comparison is calculated
Each column uses the wiki’s income formula: base $/s x mutation x size factor. Base income comes from the same 265-pet dataset as the pets list. The size factor is ratio^(37/60) up to a 125x weight ratio and grows more slowly above that. Mutations here are single mutations; if your pet has two, run it through the mutation calculator and compare the result by hand.
“Speed to reach nest” is the biome requirement from the wiki’s Speed page. Pets from Robux eggs, Rifts, the Laboratory, events and fusions have no nest, so the row says n/a.
How heavy does your pet need to be?
The most useful comparison is usually your current pet, at its real weight, against a normal-weight pet from the next biome. The table below shows the weight ratio your pet needs before it out-earns that next pet. Both pets have no mutation.
| Your pet (base $/s) | Next pet at normal weight | Income gap | Weight ratio to match |
|---|---|---|---|
| Brr Brr Patapim ($1.8K) | Leviathan ($220K) | 122x | about 12,000x, not realistic |
| King Snake ($3.5M) | Ice Dragon ($65M) | 18.6x | about 114x |
| Mosasaurus ($180M) | Unicorn ($1B) | 5.6x | about 16x |
| Electric Eel ($200M) | Luminous Electric Eel ($1.75B) | 8.75x | about 34x |
| Nightflame ($3B) | Aetheron ($6.9B) | 2.3x | about 3.9x |
| Aetheron ($6.9B) | Spirit World Guardian ($15B) | 2.17x | about 3.5x |
| Cthulhu ($3B) | Luminous Cthulhu ($6.5B) | 2.17x | about 3.5x |
| Unicorn ($1B) | Kitsune ($1.8B) | 1.8x | about 2.6x |
| Ice Dragon ($65M) | Lava Dragon ($100M) | 1.54x | about 2x |
| El Maja ($130M) | Mosasaurus ($180M) | 1.38x | about 1.7x |
The pattern: in the early biomes, the next tier is so far ahead that no realistic weight closes the gap, so you should always move up. From Snow onward, the top pets of neighbouring biomes are within 1.4x to 2.3x of each other, and an egg hatched at 2x to 4x weight is enough to beat a normal-weight pet one biome higher. That is why late-game players compare cards in $/s, not by rarity name.
Should I trade pet X for pet Y?
The tool can tell you which pet earns more in your pen. It cannot tell you whether a trade is fair. Three things it leaves out:
- Scarcity. Limited pets (Halloween Robux egg, Luminous Egg, concert and event rewards) stop being obtainable, and their trade value can rise above their income. Income alone underrates them.
- Your slots. If you have an empty pen slot, you do not need to swap at all; add the new pet and keep both. The swap check assumes your pen is full.
- Your Speed. A pet from a biome you can already reach can be stolen again after a nest reset. A pet from a biome you cannot reach yet is harder to replace.
Use the swap line as “how much faster would I earn”, then decide on the rest yourself.
Why there is no “income per egg cost” column
Nest eggs cost nothing; you steal them. The paid eggs (Luminous, Monster, Extinction, the Halloween egg) are sold for Robux and their per-pet odds are mostly not published. The wiki gives a 1% Luminous reroll chance and community guides give the Halloween Dimension Egg’s tier split (51 / 24 / 18 / 6.5 / 0.5%), but neither says which pet sits in which slot. Any “income per Robux” number would have to invent those odds, so we left it out. The Luminous pets guide works through the one case where the odds are known.
Sources & last checked
Last checked: November 4, 2026.
- rblxguide.com pet index - Steal an Egg Wiki mirror, synced October 24, 2026; still 265 pets on November 4
- rblxguide.com speed and biome requirements - synced October 24, 2026
- rblxguide.com income calculator - size formula (labelled beta)
- rblxguide.com mutations - multipliers
- ofzenandcomputing: Halloween Part 2 guide - Halloween egg tier odds
- Steal an Egg Wiki (Fandom) - CC BY-SA 3.0