Puppy Size Predictor

Free puppy growth calculator

Mixed Breed Puppy Size Calculator

Estimate how big your puppy will get, including adult weight, height, and growth timeline—even when its ancestry is unknown.

100-breed modelPrivate by designRange, not guesswork
1 Tell us about your puppy
Improve your prediction Add parent details, sex, and body condition

Parent weights have the strongest effect here. Use known adult weights rather than guesses.

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The honest version

Puppies of the same age do not all grow at the same rate.

“Double the weight at 16 weeks” is a common rule of thumb, but it treats every dog as if it grows at the same speed. Toy dogs mature much sooner than giant dogs. This calculator uses age and weight together with a growth pattern matched to the known breed or expected adult size.

If available, parent weights, sex, and body condition provide additional context. The result remains a range because genetics, nutrition, and health cannot be captured perfectly by an online form.

For a mixed breed puppy, choose “Mixed / unknown breed.” You can enter two likely breeds when you know them, or use an expected adult size when you do not. Known parent weights can improve the estimate; without them, the range stays wider to reflect uncertain ancestry.

Read the complete methodology →

Puppy growth guide

When do dogs stop growing?

Height usually settles before a young dog finishes filling out. Larger dogs generally need more time.

XS

Toy dogs

8–12 months

Fast early growth, with most adult height reached within the first year.

S

Small dogs

10–12 months

Often close to adult weight around their first birthday.

M

Medium dogs

12–15 months

May gain muscle and body condition after height growth slows.

L

Large dogs

15–18 months

Longer, steadier development makes early estimates less precise.

XL

Giant dogs

18–24 months

Can continue maturing into their second year.

Improve your estimate

Four clues worth using together

  1. 01

    Current age and weight

    Recent, accurately measured numbers give the growth curve a stronger starting point.

  2. 02

    Breed or likely size

    Adult size changes how quickly a puppy reaches each stage of growth.

  3. 03

    Parents’ adult weights

    If known, the parents are often more informative than appearance-based guesses.

  4. 04

    Healthy body condition

    An underweight or overweight puppy can distort a weight-only projection.

Common questions

Puppy size predictor FAQ

How can I estimate how big my puppy will get?

Use current age and weight together with breed or expected adult size. The younger the puppy and the less you know about its parents, the wider the reasonable range should be.

When do puppies stop growing?

Toy and small dogs often approach adult size in their first year. Medium dogs may mature around 12–15 months, large dogs around 15–18 months, and giant breeds can keep filling out until roughly 18–24 months.

Is the puppy weight calculator exact?

No calculator can account for every genetic and health factor. This is an educational planning estimate, not veterinary advice or a guarantee.

Does paw size predict adult dog size?

No. Paw appearance cannot be reliably converted into adult pounds, so it is not included in the calculator. Read why paw size is not a dependable predictor.

Can I use this for a mixed breed rescue puppy?

Yes. Choose “Mixed / unknown breed.” If you know two likely breeds, select them; otherwise choose an expected adult size based on shelter guidance, a known parent, or a DNA result. The estimate is wider when ancestry is uncertain.

Why did my puppy’s estimate change?

Growth is uneven. Rechecking every four weeks with an accurate weight can produce a more stable estimate as your puppy gets older.

Keep growth healthy, not fast.

If your puppy is losing weight, growing unusually quickly, limping, or has a pot-bellied appearance, ask a veterinarian rather than relying on a calculator.

Learn before you estimate

Practical puppy growth guides

Use the calculator as one clue, then learn what changes the estimate and how to track growth more accurately.

Worked math

Puppy weight calculator by age

See how age changes the meaning of a weigh-in, with examples for every size class.

Understand the formula → Realistic scenarios

Four mixed-breed prediction examples

Learn how likely breeds, known parents, and unknown ancestry change the range.

See the examples → Mixed breed puppies

How to estimate adult size when ancestry is uncertain

A step-by-step method using age, weight, likely breeds, and parent information.

Read the guide → Growth stages

Puppy growth chart by expected adult size

What changes from toy to giant dogs, and why one formula cannot fit every puppy.

See the chart → Maturity

When do puppies stop growing?

Compare broad maturity windows from toy dogs through giant breeds.

See the timeline → Better inputs

How to weigh and track a growing puppy

A simple repeatable routine that makes future estimates more useful.

Track growth →

Browse all puppy growth guides →