Cavalier King Charles Spaniel puppies grow toward an adult weight of 13.0–18.1 lb (5.9–8.2 kg) under the American Kennel Club standard, which gives one range for both sexes; the chart below gives the healthy range at each month.
Quick answers
- Adults weigh 13.0–18.1 lb (5.9–8.2 kg); the AKC standard does not separate the sexes for this breed.
- At 6 months a male is usually 10.1–13.9 lb and a female 9.9–13.9 lb — about 77% of adult weight.
- At 12 months a Cavalier King Charles Spaniel is around 93% of its final weight.
- Fully grown at roughly 12 months.
Cavalier King Charles Spaniel weight chart by age
| Age | Male | Female | % of adult |
|---|---|---|---|
| 2 months | 4.0–5.7 lb1.8–2.6 kg | 4.2–6.0 lb1.9–2.7 kg | 31% |
| 3 months | 6.0–8.4 lb2.7–3.8 kg | 6.2–8.6 lb2.8–3.9 kg | 46% |
| 4 months | 7.7–10.6 lb3.5–4.8 kg | 7.7–10.8 lb3.5–4.9 kg | 59% |
| 5 months | 9.0–12.6 lb4.1–5.7 kg | 9.0–12.6 lb4.1–5.7 kg | 70% |
| 6 months | 10.1–13.9 lb4.6–6.3 kg | 9.9–13.9 lb4.5–6.3 kg | 77% |
| 8 months | 11.2–15.7 lb5.1–7.1 kg | 11.2–15.7 lb5.1–7.1 kg | 87% |
| 10 months | 11.9–16.5 lb5.4–7.5 kg | 11.7–16.3 lb5.3–7.4 kg | 91% |
| 12 months | 12.1–16.8 lb5.5–7.6 kg | 11.9–16.8 lb5.4–7.6 kg | 93% |
| 18 months | 12.8–17.6 lb5.8–8.0 kg | 12.6–17.6 lb5.7–8.0 kg | 98% |
| 24 months | 13.0–18.1 lb5.9–8.2 kg | 13.0–18.1 lb5.9–8.2 kg | 100% |
Weigh on the same scale at the same time of day where you can. The trend across several weighings tells you far more than any single row.
Reading the range
The American Kennel Club gives one weight range for Cavaliers, 13 to 18 lb, rather than separate figures for males and females, so the two columns above are identical.
Males in the breed do generally finish heavier than females, but the standard does not put a number on it and the VetCompass study did not split its bodyweight figure by sex. Expect a female to sit lower on the chart than a male of the same age, and do not read that as underweight.
How a small breed grows
Cavalier King Charles Spaniels reach roughly 31% of adult weight at 2 months, about 59% at 4 months, and around 93% at 12 months.
A toy breed is already at 36% by 2 months and effectively finished by its first birthday. A Cavalier King Charles Spaniel that still looks unfinished at 10 months is therefore usually on schedule rather than behind, and is close to full size by its first birthday.
Where to go next
- Estimate your own puppyEnter an age and weight to project this breed’s adult size.
- Compare across small breedsThe same curve applied to every small breed on the site.
- Puppy growth chart by ageAll five size classes in one table, and what the ranges mean.
- Body condition scoreThe 9-point scale vets use, and why it beats the scale alone.
Other small breeds
Frequently asked questions
What is the average weight of a Cavalier King Charles Spaniel?
An adult Cavalier King Charles Spaniel weighs 13.0–18.1 lb (5.9–8.2 kg), according to the American Kennel Club breed standard, which gives one range for both sexes.
How much should a 3 month old Cavalier King Charles Spaniel weigh?
A male is typically 6.0–8.4 lb (2.7–3.8 kg) and a female 6.2–8.6 lb (2.8–3.9 kg) — around 46% of adult weight.
How much should a 4 month old Cavalier King Charles Spaniel weigh?
Roughly 7.7–10.6 lb for a male and 7.7–10.8 lb for a female, about 59% of the way to adult weight.
How much does a 6 month old Cavalier King Charles Spaniel weigh?
A male is usually 10.1–13.9 lb (4.6–6.3 kg) and a female 9.9–13.9 lb (4.5–6.3 kg).
How much does a 12 month old Cavalier King Charles Spaniel weigh?
12.1–16.8 lb for males and 11.9–16.8 lb for females — about 93% of final weight, with the rest filling in over the following months.
How big will my Cavalier King Charles Spaniel get?
At 59% of adult weight by 4 months, a rough shortcut is to double a four-month weight. The calculator on the home page does this properly, using the growth curve for this size class and returning a range rather than one number.
When is a Cavalier King Charles Spaniel fully grown?
Height is usually settled first; weight keeps filling in until around 12 months. The last 7% of adult weight takes roughly as long as the jump from 3 to 4 months.
Do male and female Cavalier King Charles Spaniels weigh different amounts?
The AKC standard gives one range for both sexes, 13 to 18 lb, so the chart columns are the same. Males usually finish heavier than females, but neither the standard nor the VetCompass bodyweight study puts a number on the gap for this breed. Expect a female to sit lower on the chart than a male of the same age, and do not read that as underweight.
What size class is a Cavalier King Charles Spaniel?
A small breed, defined by adult weight. That classification determines the growth curve used here: veterinary research shows dogs of similar adult size grow at similar rates regardless of breed.
Is my Cavalier King Charles Spaniel puppy underweight if it is below the chart?
Not necessarily. The table shows the middle of the healthy range, so plenty of healthy puppies sit below it. A puppy that is consistently below and not gaining, or that has dropped from a higher line to a lower one, is worth a vet visit. A single reading below the range is not.
How can I tell if my Cavalier King Charles Spaniel is a healthy weight?
Body condition tells you more than the scale. You should be able to feel the ribs under a thin layer of fat without pressing, see a waist from above, and see the belly tuck up from the side. A dog can sit inside the weight range and still carry too much fat.
Why do Cavalier King Charles Spaniel growth charts disagree with each other?
Most published charts come from one breeder’s litters or from unsourced rules of thumb, and many do not say whether the figures are for males, females or both. The ranges here come from centile curves fitted to millions of veterinary bodyweight records, scaled to the AKC adult range, and split by sex.
Does neutering change how much a Cavalier King Charles Spaniel weighs?
The research behind these curves found neutering shifted growth trajectory only slightly, by less than the variation between individual dogs, so separate curves were not needed. Neutering is associated with a higher chance of becoming overweight in adulthood, which is a body condition question rather than a growth chart one.
Where these numbers come from
Adult weights are the breed standard figures published by the American Kennel Club. The month-by-month ranges are estimates rather than measurements of this breed: they come from growth centile curves built from around 15 million bodyweight records collected at US primary-care veterinary hospitals, published open-access by Salt and colleagues, and scaled to the adult range above. That research found dogs of similar adult size grow at similar rates regardless of breed, which is what makes the scaling valid. The records were collected between 1994 and 2013 and describe dogs attending veterinary clinics rather than an idealised population. The derived table, the filtering steps and the known gaps are all published, so the arithmetic here can be checked rather than taken on trust.
- American Kennel Club — Cavalier King Charles Spaniel breed standard
- American Cavalier King Charles Spaniel Club — the AKC parent club for the breed
- Summers JF, O’Neill DG, Church DB, Thomson PC, McGreevy PD, Brodbelt DC (2015). Prevalence of disorders recorded in Cavalier King Charles Spaniels attending primary-care veterinary practices in England. Canine Genetics and Epidemiology 2:4
- Salt C, Morris PJ, Wilson D, Lund EM, German AJ (2017). Growth standard charts for monitoring bodyweight in dogs of different sizes. PLoS ONE 12(9): e0182064
- Supporting dataset, University of Liverpool DataCat (CC BY 4.0)
