Bronto Income Calculator
For the Roblox game Steal An Egg. Type your Bronto's weight and mutations to see what it earns and how long it takes to afford your next upgrade.
Updated · game data from the wiki as of 30 September 2026 · changelog
Short answer: a Bronto earns $1.5M per second at its base weight of 35,000 kg with no mutations. That is $5.4B per hour. Every doubling of its weight multiplies income by about 1.53, so a Golden Bronto at twice the base weight (70,000 kg) earns $5.75M/s. Type your own Bronto's weight and mutations below.
Bronto at a glance
| Rarity | Cosmic |
|---|---|
| Biome or egg | Prehistoric |
| Base income | $1.5M/s · $5.4B/hour · $129.6B/day |
| Base weight | 35,000 kg (wiki calculator data; no second source) |
| Rank by base income | #20 of 29 Cosmic pets in our data |
| Egg grow time | 11m (wiki pet page; unverified) |
| How sure | Base income: the wiki's calculator data and the Bronto wiki page agree. Steal An Egg Time lists $1.5M/s (matches; marked "unconfirmed" there). |
Bronto income by weight
No mutations, no boosts. The size multiplier is (weight ÷ 35,000 kg)37/60 up to 125× base weight, then grows more slowly.
| × base | Weight | Size | Per second | Per hour |
|---|---|---|---|---|
| 1× | 35,000 kg | ×1.00 | $1.5M | $5.4B |
| 2× | 70,000 kg | ×1.53 | $2.3M | $8.28B |
| 5× | 175,000 kg | ×2.70 | $4.05M | $14.57B |
| 10× | 350,000 kg | ×4.14 | $6.21M | $22.34B |
| 50× | 1,750,000 kg | ×11.16 | $16.74M | $60.27B |
| 125× | 4,375,000 kg | ×19.64 | $29.46M | $106.04B |
| 250× | 8,750,000 kg | ×25.91 | $38.87M | $139.93B |
Bronto income by mutation
At base weight (35,000 kg). With two mutations the wiki disagrees with itself on whether they add or multiply, so both are shown.
| Mutation | If they add | If they multiply |
|---|---|---|
| None | $1.5M/s | same |
| Silver | $1.8M/s | same |
| Golden | $3.75M/s | same |
| Rainbow | $5.25M/s | same |
| Golden + Bloom | $4.13M/s | $4.69M/s |
| Rainbow + Parasite | $8.25M/s | $15.75M/s |
Worked example: a Golden Bronto at twice base weight
- Weight ratio: 70,000 kg ÷ 35,000 kg = 2.
- Size multiplier: 237/60 = ×1.5333.
- Golden multiplies by 2.5, so income = $1.5M × 1.5333 × 2.5 = $5.75M/s, which is $20.7B per hour.
- Saving for the The Freeze Treadmill ($3B) from $0 with only this pet: 8m 41s. A plain Bronto at base weight would take 33m 20s.
Common mistakes
- Expecting income to double with weight. A Bronto at 70,000 kg earns $2.3M/s, not double the base. To double its income it has to weigh about 3.08 times the base: 107,703 kg.
- Forgetting the 125× soft cap. For a Bronto that is 4,375,000 kg. Past it, extra weight still helps but much less: doubling from 125× to 250× adds only about 32%.
- Assuming mutations multiply. A Golden + Bloom Bronto at base weight earns $4.13M/s if mutations add (the wiki calculator's rule) and $4.69M/s if they multiply. Plan with the lower number until it's confirmed.
- Counting the x2 gamepass twice. Tick it once. If you copy this pet's income into the treadmill calculator with x2 already included, leave x2 unticked there.
Questions
How much money does a Bronto make in Steal An Egg?
At its base weight of 35,000 kg with no mutations, a Bronto makes $1.5M per second, or $5.4B per hour. Heavier and mutated Brontos make more: a Golden one at twice the base weight makes $5.75M per second.
How much is a Bronto worth in Steal An Egg?
Steal An Egg has no trade window, so there's no reliable trade value. What a Bronto is worth to you is the money it earns: $5.4B per hour at base weight, and more for a heavier or mutated one. Enter yours in the calculator above.
How heavy does a Bronto need to be to double its income?
About 3.08 times its base weight, because income grows with weight to the power 37/60. For a Bronto that is 107,703 kg.
What is the best mutation for a Bronto?
Rainbow is the strongest hatch colour at ×3.5: a Rainbow Bronto at base weight earns $5.25M per second. With Parasite on top it reaches $8.25M per second if mutations add.
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Have more than one pet? The Steal An Egg pen calculator adds up your whole pen. Or use the weight calculator, mutation calculator, fuse calculator or treadmill calculator.