Puppy Size Calculator

Estimate adult weight with data-derived growth curves—and see the sample size, observed range, and holdout error behind the answer.

Puppy Adult Weight Calculator

Estimate adult weight from sex- and size-specific curves derived from veterinary records, then see how the model performed on held-out dogs.

Know the breed? Choose a breed-specific page to add its typical adult range as context.

299,711dogs used for curve training
75,648dogs kept out for evaluation
9.5%median holdout error
Read the validation report →

How to use our dog size calculator

The calculator uses four inputs. Age and current weight are required; size and sex select a more relevant source-data curve:

  • Current Weight: Enter their weight in either lbs or kg.
  • Current Age: Input their present age in weeks or months.
  • Expected Size (Optional): Toy, small, medium, large, and giant dogs mature at different rates. If you are unsure, leave this as unknown.
  • Sex (Optional): Selects the male or female distribution. Unknown uses the combined-sex data.

How much will my puppy weigh?

The tool looks up the median fraction of eventual young-adult weight observed for comparable dogs at the selected age. It then uses a simple, inspectable formula:

Adult estimate = current weight ÷ estimated adult fraction

The displayed range comes from the 10th–90th percentile growth fractions rather than an invented percentage around the answer. Younger puppies produce wider ranges because early measurements are less informative. Read the derivation, formula, and limitations.

What this result can—and cannot—tell you

The output is a planning range for adult weight. It does not predict exact height, body condition, health, calorie needs, collar size, or crate size. Those depend on measurements and circumstances that an age-and-weight model cannot see.

Mixed ancestry, illness, nutrition, unusually small or large parents, and simple scale error can all move the adult weight outside the range. Track the trend over several weigh-ins and ask a veterinarian about unexpected growth changes.

The curves are derived from the open supporting dataset for Salt et al. (2017) and evaluated on a separate 20% holdout group. Download the derived curve table.

Popular Breed Calculators

Select a breed to combine the puppy's measurement with that breed's listed adult-weight range.

Goldendoodle

Goldendoodles are affectionate, intelligent, and come in various sizes depending on the Poodle parent.

large

Labrador Retriever

Labradors are famously friendly and energetic, requiring plenty of exercise as they grow into strong adult dogs.

very_large

German Shepherd

Loyal and highly intelligent, German Shepherds are large working dogs that mature slowly.

very_large

Golden Retriever

Goldens are sturdy, muscular dogs known for their dense, lustrous coats and friendly demeanor.

large

Yorkshire Terrier (Yorkie)

Yorkies are compact toy terriers known for their long, silky coats and feisty personalities.

toy

Cavapoo

A delightful cross between a Cavalier King Charles Spaniel and a Poodle, known for being incredibly affectionate.

small

Labradoodle

Energetic and intelligent, Labradoodles mix the trainability of a Lab with the low-shedding coat of a Poodle.

large

Bernedoodle

A striking blend of the Bernese Mountain Dog and Poodle, yielding a large, loyal, and goofy family pet.

very_large
View All Breeds

Median growth fractions in the source records

These are the median fractions used by the calculator, derived from eligible dogs with a recorded young-adult outcome. See sample counts and holdout results.

Age ToySmallMediumLargeVery largeGiant
12 weeks 38%37%32%28%27%23%
24 weeks 69%70%65%64%62%58%
52 weeks 91%92%90%93%92%92%

Other Growth-Influencing Factors

Adult size and the number on a scale are influenced by factors this calculator cannot fully observe:

  • Genetics: Parents and more distant ancestry influence frame, maturation speed, and adult weight.
  • Body condition: Two dogs with the same height and frame can weigh differently because of fat and muscle.
  • Health and nutrition: Illness, parasites, appetite, and diet can change a growth trajectory and require professional assessment.
  • Measurement error: Different scales, movement, and rounding can make short-term changes look larger than they are.

Frequently Asked Questions

Answers to the most common questions about puppy growth and adult size prediction.

Is this puppy weight calculator 100% accurate? ↓
No. The model was tested retrospectively on a held-out 20% of eligible dogs, but it has not received prospective external clinical validation. The output is a planning estimate, and an individual puppy may finish outside the displayed range.
At what age do puppies stop growing physically? ↓
Small and toy breeds typically reach their adult skeletal size between 8 and 10 months. Medium breeds stop around 12 to 14 months, while large and giant breeds may continue to add muscle and bone density until they are 18 to 24 months old.
Does spaying or neutering affect my puppy's final size? ↓
The Salt et al. source study found small shifts in weight trajectory associated with neutering age, but those shifts were minor compared with normal differences among individual dogs. Ask your veterinarian about timing for your puppy rather than using an online size estimate to make the decision.
Can paw size predict how big a dog will get? ↓
Paw size may reflect general frame, but it is not reliable enough to predict a specific adult weight. An age-and-weight estimate offers another clue, but it also carries substantial uncertainty.
How much should a puppy's weight increase per week? ↓
There is no single safe weekly gain for every puppy. Breed, age, body condition, and health all matter. Repeated measurements are more informative than one number; ask a veterinarian about abrupt gains, losses, or a changing body condition.
When should I switch from puppy food to adult food? ↓
The right timing depends on expected adult size, body condition, diet, and veterinary guidance. Check the food manufacturer's life-stage directions and ask your veterinarian before changing a growing puppy's diet.
Is this puppy weight calculator 100% accurate? ↓
No. Adult weight is influenced by ancestry, health, nutrition, body condition, and measurement error. The calculator uses data-derived growth fractions and shows a population-variation range, but an individual dog can still finish outside it.
How is the adult weight estimated? ↓
We divide current weight by the median puppy-to-adult fraction observed for the selected age, size group, and sex. The wider range uses the observed 10th and 90th percentile fractions. The source, curve points, and holdout results are published on our methodology and validation pages.

Curious about puppy growth stages?

Learn more about how puppies grow, when they stop growing, and what to expect during their development phases.

View Puppy Growth Chart