FurSize / Puppy weight calculator
Puppy weight calculator
Find out how big your puppy will get, and which harness or coat size to buy now and later.
Enter your puppy's age and weight to see an estimate.
Full grown
ESTIMATEShaded band: the model's ±18% range, not a validated confidence interval.
FURSIZE
today
fully grown
Today, then fully grown. This is an estimate from size-group averages. Measure the chest for the real number.
WHAT TO BUY
| When | Chest | FurSize |
|---|
Pick a harness or coat whose chart covers your puppy's chest with about two fingers of room. Check the chest line, not the weight. When the chest passes the top of a size's range, move up.
How the estimate works
We estimate adult weight from your puppy's age, current weight and size group, then estimate chest size from weight. This model uses size-group growth curves, not a validated breed dataset. Its ±18% weight range and ±8% chest range are unvalidated estimates, not measured accuracy. Mixed breeds can vary more. Use the estimate to plan, and measure the chest before choosing a harness or coat.
Questions
How accurate is this?
It is a rough estimate. The growth model has not been checked against measured dogs yet. The displayed weight range is a placeholder of 18% in either direction. Its accuracy has not been validated. Actual differences can be larger, especially for mixed breeds. Use it as a guide for shopping. Measure before buying.
My puppy is a mix. What do I pick?
Choose the size group that fits how big the parents or the breed mix usually get. If you are unsure, run it twice with the two nearest groups and look at the range between the results.
Will I need to replace the harness?
Often, yes. Chest size grows fastest in the first months. The results show roughly when your puppy’s chest will reach new sizes so you can plan, and adjustable harnesses stretch across more of that range.
What is a FurSize number?
It is your dog’s chest girth in centimeters, rounded to a whole number and shown with inches beside it. Most harness and coat charts ask for chest girth, so the number is something you can look up on a chart directly.