How Fast Do Puppies Grow? First 12 Weeks Growth In Detail

How fast do puppies grow? They grow very fast. We know that it is a challenging time to house a growing puppy. It is also a delicate phase for your pup, both physically and emotionally. 

How fast do puppies grow once born? Refer to this checklist. To begin with, let us tell you how fast do puppies grow in the womb.

Pregnancy In Dogs 

A mama-dog is pregnant for about 63 days in general. However, it varies depending on the size of the litter. If it’s a big litter, puppies can arrive within 58 days. A small litter can take up to 72 days for delivery. 

The pregnancy is divisible into three stages. Each stage is roughly 21 days.

During the first three weeks, the development of tissues and organs is in progress. A pup would have a tiny head, the spinal column, limb buds, and the tail. It’s similar to what a human fetus would be in about three months. 

By the end of six weeks, the fetuses are like miniature dogs. They develop furs, claws, and eyelids. This is how fast do puppies grow inside the womb.

Following this period, the pregnancy is easily noticeable in the female dog. You may want to keep an eye on the signs of labor. Approximately 12 to 14 hours before giving birth, her temperature would drop. She would be reluctant to eat and show anxiety.

Canine births usually go smoothly. But, you should always have a vet’s phone number handy.

How Fast Do Puppies Grow In A Week? 

Puppies grow week by week. In the first eight weeks, all breeds grow more or less at the same rate. After that, some may grow faster than others. Let us give you a full account of how fast do puppies grow per week.

The First Three Weeks

The first three weeks is the neonatal period. In this stage, there would be not much external activity visible. The pups will just want to eat and sleep. Their eyes and ears remain firmly shut. 

When do puppies grow their most? A lot of development goes on inside them. They grow to double their body weight in this period. 

How fast do puppies grow in this period? At about two weeks, their eyes open. In another week, their ears open. Also, by the end of three weeks, puppies learn to take their first baby steps.

His little teeth will begin to show. The puppy will start making baby sounds by the end of this period. 

The pups will learn to wag their tails. They will also pick up little fights with their siblings.

Fourth To Eight Weeks  

How fast do puppies grow in 2 mos? This is the ‘toddler’ phase in puppies. They are learning a lot of new things. They will interact with their surroundings, and that includes you. 

It is the beginning of the vital socialization period in puppy. You can start to introduce them to new sights and sounds. For example, acquaint them with the sounds of TV, washing machine, etc. 

He will also learn to pee or poop by himself. Responsible breeders start potty training the pups in this period. They will also develop their full set of puppy teeth, all 28 of them.

The momma dog will start to wean her pups in this period. She will refuse to nurse for long periods. Although the pups are not ready to eat kibbles yet, you can try introducing little bits of wet food. 

Keep an eye on how fast do puppies grow in this period. Don’t separate them from their canine family as yet. That will prevent them from learning important life lessons.

Puppies do a lot of wrestling among themselves in this period. They also bite each other. If the biting is too hard, the other pup gives a loud yelp. This startles the biting pup. It also helps him to learn how much biting is allowed. 

You can imitate this behavior when your pup is playing with your hand. Also, you should keep chewing toys handy to divert your pup’s mouthing tendency.  

Finally, it is during this phase that pups should get their first set of vaccinations. The vet will treat the pups for worms. Vaccinations are crucial in the growing phase.

Eight To Twelve Weeks  

This period is what we call the ‘juvenile period’ in puppyhood. The little pup is ready to go to his new home. It is also the most important socialization period. 

Keeping a note of how fast do puppies grow is important so that you do not miss the vital socialization window. If you are postponing this period, the pup may develop serious behavioral issues as an adult.

It is also the perfect time to start the first training lessons. Their minds are like the proverbial ‘blank slates’ in this period. They will easily pick up cues and commands with the right training method. 

Do remember, some pups may be a little difficult to handle during this period. You should never scold the little one or try any punishing tactic. Nothing beats the good old positive reinforcement method of training.

Four to Six Months

Their growth rate will slightly slow down in this period. If you want to know how fast do puppies grow their adult teeth, this is the period. Teething can be a challenging time and it can make a pup anxious.

This phase is similar to ‘adolescence’ in humans. The pup may show some destructive behaviors in this period. You should be consistent in your training to show him that you are the boss. Just don’t be harsh or punitive. 

While you observe how fast do puppies grow, you must not forget your responsibilities. This phase can be very unpredictable. At one moment, you can see your pup is bold. The next moment he might be trying to hide behind your legs.

You have to be the caregiver and protector too. Spend valuable time with your pup. At the same time, set down rules for the house. See that your pup obeys these rules. 

When they break the rules, try not to give them attention for some time. The ‘ignore’ strategy makes them realize that something is wrong. They soon learn to respect your boundaries.

Can You Tell How Big A Puppy Will Get?

It is relatively easier with purebred parents. You can tell how fast do puppies grow to full size. This prediction gets a little complicated with crossbred parents. Nevertheless, you can still follow the general rule of thumb on how fast do puppies grow.

According to it, a pup will not grow bigger than his biggest parent. So, if you know who the parents of your pups are, you can guess how big they will get. 

Besides this, you can try a few other ways to estimate how fast do puppies grow.

One such method refers to judging them by their paw size. It is understood that puppies with bigger paws will grow into large dogs. Likewise, small paws indicate small or medium-size growth. 

A lot depends on the breed though. For example, some large dogs such as border collies have smaller paws relative to their size. Similarly, some medium-sized breeds such as terriers can have big paws. 

How to tell how big a puppy will be full grown? You should also consider the growth curve of different breeds. 

Large dogs can grow up to three years of age. Smaller breeds complete their growth curve within one year. Medium size dogs can grow up to two years of age. 

Another rule of thumb states refers to the sixteen-week mark as an indicator. At sixteen weeks, you can double his size as an estimate of how fast do puppies grow to full size. Do note, no scientific data is supporting this assumption. It is only a general theory.

Finally, the presence of loose skin is also an indicator of future growth. As a general rule, loose skin indicates room for growth.

Do Puppies Grow Overnight?

It’s natural to compare puppy growth to various stages of human growth. Even here, we have compared different stages such as toddlers and adolescents.  

It is good to remember that humans and canines are entirely different species. The individual growth rate is also dissimilar.

The seemingly rapid growth rate of pups may raise the question of overnight growth. But, really, how fast do puppies grow? As we discussed earlier, visible growth in pups occurs by weeks and months. ‘Overnight’ may be a way of saying ‘over the weeks’.

Do Puppies Get Their Size From Mom Or Dad?

According to genetics, pups get their size from both mom and dad. Here are some general rules arranged in a chart. 

You can check out puppy growth week by week pictures. They may be available for the breed you own. Remember to be breed-specific.

Alternately, you can try out how big will my puppy get calculator. One such method takes into account the pup’s weight at six weeks or fourteen weeks. The six-week calculator is applicable for small breeds. The fourteen-week calculator is for medium to large breeds.

Multiply the size at six weeks with four to get an estimate of the adult size. For bigger breeds, you should be multiplying their weight at fourteen weeks with 2.5. 

These simple calculations can tell you how fast do puppies grow.

Another similar method considers how much weight should a puppy gain per week. To deduct this, you need to divide the current weight of your pup by the age in weeks.

Once you have this information, you can multiply it by 52. It is the number of weeks in a year. The final figure will tell you how big your puppy will grow.

Can A Puppy Grow Too Fast?

Yes, a puppy can grow too fast. It usually happens when the puppy is eating in excess. This is the reason why free-feeding is not recommended with puppies. 

Excess growth could cause a wide range of health problems. These include hip dysplasia (arthritis of the hips) and osteochondrosis. This latter condition affects the joints of pups that are rapidly growing. 

You might be having questions about how fast do puppies grow for collars. That’s why you should invest in an adjustable collar for a pup. Pay attention while putting a collar on your pup.

It should not be too tight or too loose. The collar should be such that you can pass your two fingers between the collar and neck.

How Long Does The Puppy Stage Last?

To understand how fast do puppies grow, you need to be familiar with growth plates. They are also called physis or epiphyseal plates. These are cartilage zones at the end of bones.

In puppies, new bones grow out of growth plates. When do puppies stop growing? As they reach a certain age, the growth plate will completely ossify and fuse with the bone.

This age varies according to the types of breeds. When do small breed puppies grow the most? Their growth plates stop being active at about one year. The growth phase for medium to large dog breeds is longer. It can continue up to two to three years.

The vet will be checking the growth plates. It is one of the ways by which the doctor would ascertain the growth stage. She would run her hand across the puppy’s rib cage. If the ends of the ribs have ‘knots’, it means the growing phase is still active.

Before the growth plates close, they are soft and vulnerable to injuries. It is advisable not to exercise your pup excessively until at least eighteen months of age. Injuries to growth plates can result in misshapen limbs among other problems. 

Even slight stress on the growth plates can align it at an unwanted angle. Such an angular orientation can make the pup more susceptible to injuries. Knowing this fact is vital to properly train your pet. 

How can an experienced breeder tell the difference between a neutered and an intact pup? The answer may lie in the influence of sex hormones on growth plates. One of the functions of sex hormones is to regulate growth. Inhibiting their production at an early age can have a negative effect on the growth of the animal.

Do Puppies Get Fat Before They Grow?

No, they do not. If your puppy is chubby, it means that you are overfeeding him. How to understand that your pup is overweight? There are a few indicators to it. 

You should be able to feel the ribs. Press your hand at the side of his body. If you cannot feel the ribs there, your puppy may be obese. 

Irrespective of your puppy’s growth rate, you should be able to see their tummies tuck. Always keep a close look at how fast do puppies grow to full size 25 pounds.

We already warned you about the problems of too much exercise for your puppies. That said, you should also know how fast do puppies grow starts problem. The phase between eight to twelve months is particularly important.

This is the ‘teenage’ time for most dogs. They require strong guidance in this period. Look up credible information on puppy training.

Can You Overfeed A Puppy?

If you are not careful with his diet, overfeeding is a possibility. You need to follow certain precautions to prevent this from happening. 

Don’t feed table scraps to your puppies. Your food may consist of more fat and carbohydrates than the puppy needs. 

Follow feeding instructions on product labels to decide how much food to give your puppy. And, finally, keep the treats to a minimum. 

Pups lose their ‘baby fat’ by the time they are six to eight weeks. By this time, they are also fully weaned. Following this period, you should get special food for puppies. Avoid bad dog food ingredients to help your puppy grow healthy and always look for Dog sickness symptoms.

Don’t feed milk to puppies as a replacement for mother’s milk. Packaged milk contains lactose which is difficult for puppies to digest.

What Are The Best Times To Feed A Puppy?

Divide your puppy’s meals into three servings. Experts agree that the best time to feed a puppy is at 7 a.m, 12 p.m, and 5 p.m. 

This should allow them sufficient time to digest their meals. It also makes sure that your pup does his business once before bedtime.

Takeaway-How Fast Do Puppies Grow  

Puppies grow very fast. At times, it may look like they are growing overnight. They grow by weeks and you should keep a close watch on their growth. 

Start basic training when your pup is ready. Also, do not miss the vital socialization window. 

Get to know more about how each dog breed’s puppy grows to have an understanding before getting a puppy. Here’s the Cavapoo puppy guide and Goldendoodle puppy guide.

Here’s wishing a healthy life to your pups!

Rajkumar Ravichandran

Welcome to Learn About Pet. My name is Rajkumar Ravichandran and I love all pets, travel, and amazing food. I write about my passion and personal experience caring for multiple pets in this blog! ❤️