How big will my puppy get?

Enter your puppy’s current weight, age and expected size class. We divide the current weight by the fraction of adult weight a puppy of that size has usually reached at that age, giving a predicted adult weight and a likely range.

How accurate is a puppy weight calculator?

Predictions are usually accurate to within about 10–15% when you know the breed or size class. Accuracy improves after 8 weeks of age, and the range narrows as the puppy grows. It is an estimate — your vet can assess your individual puppy.

At what age do puppies stop growing?

Small breeds finish around 8–12 months, medium breeds around 12–14 months, large breeds around 14–18 months, and giant breeds can keep filling out until about 24 months.

Can I predict a mixed-breed puppy’s adult weight?

Yes — use the mixed-breed version. Because parentage is uncertain, pick the size class that best matches your puppy (or average the two parent sizes) and expect a slightly wider range.

Puppy weight predictor

How big will your puppy get?

Enter your puppy’s age and weight to predict its adult size — purebred, mixed breed, or pick your breed below. This puppy weight estimator is built on veterinary growth standards.

A young puppy sitting and looking up at the camera — Photo: Rishu Bhosale / Pexels

Current weight

Current age

Breed (optional — type any breed)

Expected size

Sex (optional — sharpens the estimate)

Predicted adult weight

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likely —

now — — grown adult —

Enter your puppy’s weight and age.

Good to know

General guidance only — an estimate, not veterinary advice. Always check with your vet about your pet’s growth, weight and diet.

How this was calculated

We use the age-percentage method: a puppy reaches a known fraction of its adult weight at a given age, and that fraction depends on its size class. So adult weight ≈ current weight ÷ the fraction of adult weight reached at this age. The fractions are anchored to published milestones — small breeds are ~25% of adult weight at 6 weeks, medium ~40% at 14 weeks, large ~50% at 20 weeks, giant ~50% at 24 weeks, and most dogs reach ~75% by 6 months. Predictions are typically accurate to within 10–15%, and tighten as your puppy gets older.

Source: WALTHAM Petcare Science Institute — puppy growth charts. Full method on our methodology page.

Mixed-breed estimate →How much to feed →

Built by the PawGauge team, reviewed against cited veterinary sources. Last reviewed 29 June 2026.

About our figures →

Predict by breed

Each breed page sets the right growth curve and shows the typical adult range.

How the puppy weight calculator works

A growing puppy puts on weight along a fairly predictable curve, and the shape of that curve depends on how big the dog will eventually be. Small breeds shoot up fast and finish early; giant breeds grow more slowly and keep filling out for up to two years. Because of that, the same weight at the same age means very different adult sizes for a Yorkshire Terrier and a Great Dane.

The calculator uses the age-percentage method: it works out what fraction of its adult weight a puppy of your dog’s size class has usually reached at its current age, then divides the current weight by that fraction. Published milestones anchor the curve — for example small breeds are about a quarter of their adult weight at 6 weeks, and most dogs reach roughly three-quarters of adult weight by six months.

Treat the result as a well-grounded estimate, not a guarantee. Real growth is affected by genetics, nutrition, neutering and health, so we show a likely range as well as a single figure. For anything health-related — your puppy seems over- or under-weight, or isn’t growing as expected — talk to your vet. Expecting a litter? Our dog pregnancy estimator works out the due date and a week-by-week timeline.

Puppy weight questions

How big will my puppy get?: Enter your puppy’s current weight, age and expected size class. We divide the current weight by the fraction of adult weight a puppy of that size has usually reached at that age, giving a predicted adult weight and a likely range.
How accurate is a puppy weight calculator?: Predictions are usually accurate to within about 10–15% when you know the breed or size class. Accuracy improves after 8 weeks of age, and the range narrows as the puppy grows. It is an estimate — your vet can assess your individual puppy.
At what age do puppies stop growing?: Small breeds finish around 8–12 months, medium breeds around 12–14 months, large breeds around 14–18 months, and giant breeds can keep filling out until about 24 months.
Can I predict a mixed-breed puppy’s adult weight?: Yes — use the mixed-breed version. Because parentage is uncertain, pick the size class that best matches your puppy (or average the two parent sizes) and expect a slightly wider range.