On this page
Formula
W₂ = W₁ ÷ (A₁ + 10) × (A₂ + 10); XP per Age = round(20 × Age^2.02)
- W₁
- the pet's current weight in kg
- A₁
- the pet's current Age
- A₂
- the Age you want to project to
- W₂
- the pet's weight at Age A₂
- Age^2.02
- the Age being completed, raised to the power 2.02, for the XP needed to reach the next Age
What the Grow a Garden pet calculator does
In the Roblox game Grow a Garden, a pet’s weight drives most of its passive abilities: heavier pets get shorter cooldowns, higher chances and bigger effects. Weight rises every time the pet gains an Age, and the rise follows a simple, predictable rule. This grow a garden pet calculator uses that rule to answer the three questions players ask most: how heavy will this pet be at a given Age, what Age does it need to reach a target weight, and how much XP and time stand between here and there.
Unofficial fan tool: not affiliated with or endorsed by the game’s developers or Roblox Corporation. Game data last checked: October 2026.
How to use the grow a garden pet calculator
- Pick Weight at an age to project forward, or Age for a weight to work out a target.
- Enter the pet’s current weight in kg and its current Age, exactly as the pet card shows them.
- Enter the target Age or target weight.
- Leave XP per second at the base 0.5, or raise it if XP boosters or a mutation speed your pet up.
The result shows the projected weight or Age, the XP needed, the time at your XP rate, and four reference figures: the Age 1 weight, the BaseWeight, the weight added per Age and the weight at Age 100. In weight mode a milestone table lists the pet’s weight at Ages 1, 25, 50, 75, 100, 200 and 500.
The grow a garden pet weight formula
The Grow a Garden Wiki gives the standard weight rule as W(A) = B × (A + 10) ÷ 10, where B is the pet’s hidden BaseWeight and A is its Age. Two facts follow:
- At Age 1 a pet weighs 1.1 × B, and each extra Age adds 0.1 × B, which is one-eleventh of the Age 1 weight.
- The weight at any Age is proportional to Age + 10. That is why you never need to know B: divide by the current Age + 10 and multiply by the target Age + 10.
Working it out by hand
Say a pet weighs 3.6 kg at Age 8 and you want its weight at Age 62.
- Current weight ÷ (current Age + 10) = 3.6 ÷ 18 = 0.2 kg per unit.
- Multiply by the target Age + 10: 0.2 × 72 = 14.4 kg.
To reverse it and find the Age for 9 kg: 9 ÷ 0.2 = 45, then 45 − 10 = 35, so the pet reaches 9 kg at Age 35. If the answer is not a whole number, round up, because the pet only passes the target on the next full Age.
The same numbers give the BaseWeight: 10 × 0.2 = 2 kg, so this pet showed 2.2 kg at Age 1.
Weight and XP by Age
The table shows how many times its Age 1 weight a standard pet weighs at each Age, and the total displayed XP from Age 1, summed from round(20 × Age^2.02). The last column is the time at the base 0.5 XP per second with the pet always fed.
| Age | × Age 1 weight | XP from Age 1 | Days at 0.5 XP/s |
|---|---|---|---|
| 10 | 1.82 | 5,922 | 0.1 |
| 25 | 3.18 | 103,781 | 2.4 |
| 50 | 5.45 | 868,329 | 20.1 |
| 75 | 7.73 | 2,984,794 | 69.1 |
| 100 | 10 | 7,152,163 | 165.6 |
| 200 | 19.09 | 58,458,516 | 1,353.2 |
| 500 | 46.36 | 934,544,088 | 21,633 |
The XP column climbs much faster than the weight column. Weight grows in a straight line with Age, while the XP cost of each Age grows roughly with the square of the Age. At the base rate alone, high Ages are out of reach, which is why players lean on XP boosters, XP-granting pets and mutations. Enter your real XP rate in the grow a garden pet calculator to get a realistic time.
Real-life uses
- Before trading. Check what a young pet will weigh at Age 50 or 100 so you compare pets on their future weight, not today’s.
- Choosing which pet to level. Two pets of the same type with different BaseWeights end far apart; the one that hatched heavier stays heavier at every Age by the same ratio.
- Planning XP boosters. Compare the time at 0.5 XP per second with your boosted rate to see whether a booster is worth it for a target.
- Spotting Huge hatches. The wiki lists a normal egg-pet Age 1 range of about 0.88–2.20 kg and a Huge range of about 3.52–8.80 kg (Huge pets get a ×4 weight modifier). Back-calculating the Age 1 weight puts a pet in context.
Common mistakes
- Scaling by Age instead of Age + 10. Doubling the Age does not double the weight. A pet at Age 10 is not twice as heavy as at Age 5; it is (20 ÷ 15) = 1.33 times as heavy.
- Confusing Age 1 weight with BaseWeight. The Age 1 weight is 10% above BaseWeight. Use the right one when you compare with community lists.
- Forgetting hunger. XP stops when the hunger bar is empty, so real time is longer than the estimate if the pet goes unfed.
- Using a rounded display weight for big projections. A weight shown to two decimals can shift a projection to Age 500 by a few tenths of a kg. Use the weight from the highest Age you have seen for the best estimate.
- Expecting every pet to follow the rule. A few pets have fixed stats or special scaling that ignore weight, so treat their projections as weight only.
Glossary
- Age: the pet’s level, shown on its card. It rises when XP fills the bar.
- BaseWeight: the hidden weight the formula scales from; Age 1 weight ÷ 1.1.
- XP: experience. A fed pet earns 0.5 XP per second before boosts.
- Huge: a rare egg outcome with a ×4 weight modifier.
- Hunger: the food bar that must stay above zero for the pet to keep aging.
Worked examples
A fresh hatch grown to Age 50
A pet that showed 1.32 kg at Age 1, projected to Age 50 at the base 0.5 XP per second.
Inputs (Weight at an age): Current weight = 1.32 kg; Current age = 1; Target age = 50; XP per second = 0.5 XP/s
W₂ = 1.32 kg ÷ (1 + 10) × (50 + 10) = 7.2 kg XP = Σ round(20 × Age^2.02) for Age 1 to 49 = 868,329 XP Time = 868,329 ÷ 0.5 XP/s = 20.1 days (482 hours) of fed, active time
Answer: A 1.32 kg pet at Age 1 weighs 7.2 kg at Age 50.
Projecting a mid-age pet to the cap
A 4.8 kg pet at Age 30, projected to the maximum Age of 500.
Inputs (Weight at an age): Current weight = 4.8 kg; Current age = 30; Target age = 500; XP per second = 0.5 XP/s
W₂ = 4.8 kg ÷ (30 + 10) × (500 + 10) = 61.2 kg XP = Σ round(20 × Age^2.02) for Age 30 to 499 = 934,362,220 XP Time = 934,362,220 ÷ 0.5 XP/s = 21,628.8 days (519,090 hours) of fed, active time
Answer: A 4.8 kg pet at Age 30 weighs 61.2 kg at Age 500.
Age needed for a 6 kg pet
A pet hatched at 1.65 kg, and the first Age at which it weighs 6 kg or more.
Inputs (Age for a weight): Current weight = 1.65 kg; Current age = 1; Target weight = 6 kg; XP per second = 0.5 XP/s
Age = ⌈6 kg ÷ 1.65 kg × (1 + 10) − 10⌉ = ⌈30⌉ = 30 XP = Σ round(20 × Age^2.02) for Age 1 to 29 = 181,868 XP Time = 181,868 ÷ 0.5 XP/s = 4.2 days (101 hours) of fed, active time
Answer: A 1.65 kg pet at Age 1 reaches 6 kg at Age 30, about 181,868 XP away.
Exactly ten times the Age 1 weight
Edge case: 22 kg is exactly 10 × the 2.2 kg Age 1 weight, which the formula reaches at Age 100 on the dot.
Inputs (Age for a weight): Current weight = 2.2 kg; Current age = 1; Target weight = 22 kg; XP per second = 0.5 XP/s
Age = ⌈22 kg ÷ 2.2 kg × (1 + 10) − 10⌉ = ⌈100⌉ = 100 XP = Σ round(20 × Age^2.02) for Age 1 to 99 = 7,152,163 XP Time = 7,152,163 ÷ 0.5 XP/s = 165.6 days (3,973 hours) of fed, active time
Answer: A 2.2 kg pet at Age 1 reaches 22 kg at Age 100, about 7,152,163 XP away.
Assumptions and limitations
- Unofficial fan tool. Not affiliated with, endorsed by or connected to the developers of Grow a Garden or Roblox Corporation. Game data last checked October 2026 against the Grow a Garden Wiki.
- Uses the standard pet weight rule W(A) = BaseWeight × (Age + 10) ÷ 10, so each Age adds one-eleventh of the Age 1 weight. A few pets with fixed stats or special scaling do not follow it.
- The current weight you enter is rounded in the game's display, so back-calculated Age 1 weight and BaseWeight can be off by a few hundredths of a kg.
- XP per Age is the rounded value the game shows, round(20 × Age^2.02), and Ages are capped at 500.
- Time assumes the pet gains XP the whole time at the rate you enter (0.5 XP per second by default) and is never left hungry, because an empty hunger bar stops aging.
- Weight boosts that change BaseWeight (such as resets that add 0.1 kg) are not modeled; recalculate after one happens.
Frequently asked questions
How do you calculate a pet's weight in Grow a Garden?
Divide the current weight by the current Age plus 10, then multiply by the target Age plus 10. A 2.8 kg pet at Age 4 weighs 2.8 ÷ 14 × 30 = 6 kg at Age 20.
How much does a pet grow at Age 100?
A standard pet weighs exactly 10 times its Age 1 weight at Age 100, because (100 + 10) ÷ (1 + 10) = 10. At the Age 500 cap it reaches about 46.36 times its Age 1 weight.
How do you calculate a pet's base weight in Grow a Garden?
BaseWeight = 10 × current weight ÷ (current Age + 10). The Age 1 weight shown in game is 1.1 times the BaseWeight, so a pet that showed 1.98 kg at Age 1 has a BaseWeight of 1.8 kg.
How much XP does a pet need to level up?
The XP to go from one Age to the next is 20 × Age^2.02, rounded. Age 1 to 2 needs 20 XP, Age 2 to 3 needs 81 XP, and the cost keeps rising, so later Ages take far longer.
Why does my pet stop gaining Age?
Normal aging needs food. When the hunger bar reaches zero the pet stops gaining XP until you feed it a crop, so the time estimates here only count time while the pet is fed.
What is the max pet age in Grow a Garden?
Age 500 is the maximum listed on the Grow a Garden Wiki when this page was checked in October 2026. The calculator does not project beyond it.
Is this an official Grow a Garden tool?
No. It is an independent fan calculator built from the community wiki's published formulas. It has no connection to the game's developers or Roblox.
Sources
- Pets (Age, Pet Weight and XP requirements) — Grow a Garden Wiki (Fandom). Checked October 10, 2026.