Dog litter size calculator: how many puppies will my dog have?

How many puppies do dogs usually have?

The largest study so far counted 10,810 litters of 224 breeds registered with the Norwegian Kennel Club. The average was 5.4 puppies, but size made a big difference: 3.5 in miniature breeds and 7.1 in giant breeds. An Italian census of 3,293 puppies found the same pattern and published the average for each weight band, which is what the calculator uses:

The averages are measured; the range is not. To show how much litters vary, the calculator spreads the average over a Poisson curve, the same kind of model the Italian researchers used. Treat it as a rough guide: about one litter in ten will be smaller than the range and one in ten larger.

Why bigger dogs have bigger litters

In the Norwegian data, the size of the breed was the strongest single influence on litter size, ahead of age and mating method. The Italian census confirmed that the number of puppies rose steadily with the mother's weight and height, and found that short, stocky (brachymorph) breeds had the smallest litters for their size.

Breed still matters among dogs of the same weight. Labrador Retrievers in the Italian census, for example, had litters about a quarter smaller than Golden Retrievers, even though the two breeds are a similar size.

Does the mother's age affect litter size?

Yes, mainly at the two ends of her breeding life. Dams over about 6 years tend to have smaller litters, and the Norwegian study found the drop with age was steepest in large breeds. In a study of 915 Entlebucher Mountain Dog litters, each extra month of the mother's age meant 0.01 fewer puppies at birth, or about one puppy fewer for every 8 years. At the young end, first litters from miniature and small-breed dams under a year old were smaller, while large and giant breeds showed no such effect.

Age matters for the puppies as well as the count. In the Norwegian litters, stillbirths became more likely as the mother got older, and the risk was three times higher when a dog had her first litter after the age of six.

What else affects how many puppies a dog has?

• Mating method. Whether she was mated naturally or by artificial insemination made a measurable difference in the Norwegian study.
• Not parity or season. The same study found no effect of how many litters she had had before, or of the time of year.
• Her health and condition. A fit dog at a healthy weight, fed well through pregnancy, is best placed to carry and raise her litter. Our pregnancy week-by-week guide covers feeding and care.

How can I find out how many puppies she is carrying?

An X-ray late in pregnancy is the most reliable way: the puppies' skeletons show from about day 45, and the Merck Veterinary Manual names an X-ray after day 55 as the best method to count them. An earlier ultrasound confirms the pregnancy and that the puppies are alive, but the X-ray gives the more accurate count. Knowing the number matters on the day, because it tells you whether she has finished or a puppy is still to come. The dog due date calculator shows when to book the X-ray.

How many puppies survive?

In the Norwegian litters, about 8% of puppies died in their first week: 4.3% were stillborn and 3.7% died in the following days, and a quarter of litters lost at least one puppy. Losses after that were small, about 1% of puppies between one and eight weeks old. Larger litters and older mothers carried a higher risk, so have your vet's number ready and check every puppy is feeding in the first days.