Kitten Growth Estimate
Free Kitten Growth Estimate calculator with clear step-by-step results.
About Kitten Growth Estimate
Healthy kittens gain roughly 100 grams a week for the first several months, so the ratio between actual and expected weight for age gives a growth index. That index is carried forward to the target age and capped at expected adult weight, since growth plateaus rather than continuing linearly.
Formulas
Expected weight for age
Grams = 100 + age in weeks x 100, capped at adult weight
Projected weight
Projected = expected weight at target age x (current weight / expected weight now)
Worked example
With the default values below, Kitten Growth Estimate returns Projected weight at the target age of 1,700. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Current ageaccepts 0.5–52 weeks
- 8 weeks
- Current weightminimum 50 g
- 900 g
- Age to project toaccepts 1–60 weeks
- 16 weeks
- Expected adult weightaccepts 1–12 kg
- 4.5 kg
Results
- Projected weight at the target age
- 1,700 g
- Expected weekly weight gain
- 100.0 g/week
- Growth index versus a typical kitten
- 1.000 x
- Current weight as a share of adult weight
- 20.0% %
Step by step
- 1Values used
- 2Expected weight for age
- 3Projected weight
- 4Projected weight at the target age= 1,700 g
- 5Expected weekly weight gain= 100.0 g/week
- 6Growth index versus a typical kitten= 1.000 x
- 7Current weight as a share of adult weight= 20.0 %
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- A rough growth guide only. Weight trends matter far more than a single reading, and any kitten failing to gain weight should be assessed by a veterinarian.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
A rough growth guide only. Weight trends matter far more than a single reading, and any kitten failing to gain weight should be assessed by a veterinarian.
Frequently Asked Questions
What does a growth index below 1 mean?
The kitten is lighter than typical for its age. That can be normal for a small breed or a large litter, but persistent slow gain warrants a veterinary check for parasites or underfeeding.
When do kittens stop growing?
Most reach adult weight between nine and twelve months, though large breeds such as Maine Coons continue filling out until two to four years.