The world record according to Guinness is the whopping twenty-four puppies,. Typical litter size tends to range from 1 to 12 puppies, with an average of 5 to 6 puppies in all dogs. However, large breeds can have up to 15 offspring. It's a wide range and depends on your dog's species, size, health, and pregnancy history.
The number of puppies your dog can have varies a lot. Smaller breed dogs usually have 1 to 4 pups per litter. The breed of dogs selected for mating and, therefore, breeding surely has an impact on the number of puppies produced. Smaller breeds usually give birth to smaller litters compared to larger breeds.
In the old days, the practice consisted of counting the number of nipples the dog had to obtain an average number of puppies to expect in a litter (the so-called half-nipple rule), but this practice proved to be inaccurate for many reasons. This will not only allow the veterinarian to count the number of puppies present, but also to inspect their bone structure and observe any abnormalities. That's why Shih Tzu, Pomeranians and Chihuahuas have litters that usually range from one to four puppies, while Cane Corsos, Great Danes and other giant breeds usually give birth to eight or more puppies. Towards the end of your dog's pregnancy, the vet will likely be able to feel the mother's belly or take an X-ray to determine an “exact number of puppies in their belly” (although it can be easy to miss one of the puppies, so you'll never know for sure until the little wiggles start to come out).
For example, dogs of breeds that normally produce litters of five puppies can only produce one or two for their first litter. Let's say that for your breed the average litter size is between 8 and 12 puppies, some breeders want to help their mother reach 11, 12 or even 13 puppies. In 2004, a Neapolitan mastiff named Tia became the mother of the largest litter ever documented, when she gave birth to 24 puppies by cesarean section. In general, large dogs have larger litters because, biologically, they can safely carry more puppies.
You can't put two parents who previously produced large litters and expect puppies to produce large litters two years later as well. Therefore, the number of puppies produced tends to increase the larger the dog, but this is not a black and white statement. Just because my dog, who is a Jack Russell Chihuahua and Boston Terrier, gave birth on his own to a litter of 12 puppies but only 11 survived. As mentioned above, litter size varies based on several factors, but for the sake of discussion, we'll assume you have around five puppies in each litter.
For example, a 45-pound Labrador Retriever can produce a litter of only five or six puppies, while an 85-pound Lab can produce a litter of 10 or more. Also having mating at the end of the fruiting period of the female dog and not from the beginning is a factor that leads to having more puppies.