Brittany Growth Chart: How Big Will Yours Get?

The honest answer starts with the official standard: Brittany adults run 30 to 40 lb per the AKC breed standard. Your puppy's own weight and age narrow that further.

Run your own numbers in the puppy weight calculator — it combines this breed range with two published growth formulas and your puppy's current weight.

How medium dogs grow

Medium-size puppies grow at a pace between the two ends of the size spectrum. Toy breeds reach about half their adult weight around 12 weeks, while giant breeds don't reach that halfway point until around 26 weeks. Medium puppies grow steadily in between, without the fast early sprint of a toy breed or the long, slow climb of a giant. Veterinary sources place the general window for reaching adult body size in medium dogs around 9 to 12 months, with growth slowing noticeably after about 6 months.

Individual dogs vary even within the medium class, so the best way to track a puppy's progress is against a weight range for its expected adult size instead of one fixed number. A range accounts for normal differences between dogs and gives a clearer signal than a single target figure. Watching the trend across several checkups matters more than any one weigh-in. Some variation among dogs is normal, so a puppy that tracks above or below its range usually just needs a feeding-amount adjustment.

Why we don't publish a week-by-week weight table

Charted growth curves exist in veterinary research, but no source publishes the underlying week-by-week numbers in verifiable form — so we won't fake one. Our methodology page explains exactly what data this page uses and where it comes from. For tracking, weigh your puppy regularly and compare against the adult range above, or read what to track week by week.

Common questions

How big will a Brittany get?

30 to 40 lb at maturity, per the AKC standard. Individual dogs can land outside the standard, especially mixes and outlier bloodlines.

Is my Brittany puppy on track?

Enter their age and current weight in the weight predictor. If the formula estimate lands far outside the breed range, the tool flags it — that usually means tracking above or below standard, and it's worth mentioning at your next vet visit.

When do they stop growing?

Growth timing varies by size class more than by breed — our guide on when dogs stop growing covers what the research supports.

Estimates, not guarantees, and not veterinary advice. Sources for every number on this page: methodology.