Chihuahuas are one of the smallest dog breeds and are incredibly popular with dog lovers everywhere. It’s no surprise – they’re cute, adaptable, and great fun to have around. My Chi brightens every day and has made me completely fall in love with the breed. 

Chihuahua Growth & Weight Stages - Age Milestones to Know

Adult Chihuahuas are little, but can you imagine just how tiny a Chihuahua puppy is? In the first couple of months, they’re smaller and weigh less than a guinea pig!

So, how quickly do they grow? And when do they stop growing? We’ll cover everything you need to know about Chihuahua growth and weight stages. 

Why Is It Important to Track Your Chihuahua’s Growth and Weight?

Chihuahua Growth & Weight Stages - Age Milestones to Know

Whether you’re bringing a new puppy into your life or breeding your Chihuahua, you need to keep track of your puppy’s growth and weight. 

Tracking the growth of your puppy helps to ensure they’re as healthy as possible. 

By regularly weighing them you can prevent them from becoming underweight or overweight (both of which cause health issues). 

Keeping track of their growth and comparing it with what’s expected can also help you to spot any potential health issues early. 

Knowing what to expect at each growth stage helps you to be prepared and provide all the resources your puppy needs. 

How to Weigh Your Chihuahua

Chihuahua Growth & Weight Stages - Age Milestones to Know

If you’re going to regularly weigh your puppy, of course, you’ll need to know how to do it! Don’t worry, it’s pretty simple. 

If you’re breeding Chihuahuas I’d recommend weighing the puppies every few days for the first few weeks, then every week after that until they go to their new home. 

If you are adopting or buying a puppy, you won’t bring them home until they’re at least 8 weeks old. You can weigh them every week until they reach their adult size to make sure they’re on track. 

Since Chihuahuas are so tiny, bathroom scales won’t be accurate enough to pick up their very slight fluctuations in weight. Instead, you can use digital kitchen scales which are far more accurate with smaller weights. 

Alternatively, you could buy a set of veterinary scales. They are more accurate and often easier to use, but they can be pretty expensive. 

If you’re using kitchen scales, you can pop a bowl on there for your puppy to sit in. Once the bowl is on the scale, set it back to zero then put your pup inside. 

I find it can get a bit more stressful as puppies get bigger and more mischievous. If they’re wriggly, gently hold them in the bowl or on the scale to keep them as still as possible. 

Always use the same set of scales for accuracy. Stick to weighing them at roughly the same time of day, and preferably on an empty stomach to get an exact reading. 

How Can You Tell How Big a Chihuahua Will Be as an Adult? 

Chihuahua Growth & Weight Stages - Age Milestones to Know

How big your puppy will be when they’re all grown up can depend on a variety of factors. Their growth can be influenced by genetics, diet, exercise, hormones, and overall health. 

You won’t be able to predict their adult weight exactly but you can get a rough idea. 

Chihuahuas typically stop growing between the age of nine and 12 months. 

As adults, they should weigh between two and six pounds. They should stand between seven and nine inches high

Although male Chihuahuas may be slightly taller and broader than females, there won’t be a huge difference between the two sexes. 

When they reach six months old, your Chi puppy will be 75% of their full size. So you can do some quick math to guesstimate their adult height and weight.

You can also use our weight chart in the next section to predict the weight of your puppy as an adult. 

Chihuahua Growth and Weight Chart 

Chihuahua Growth & Weight Stages - Age Milestones to Know

Since this toy breed remains fairly small as an adult, they don’t have as much growing to do as larger dogs. In fact, they finish growing in half the time of larger breeds!

We’ve included a growth chart, based on the expected weight of a Chihuahua puppy at different stages. 

To use our chart, find the age of your puppy in the left column, then follow along to the right to find the weight range they should be in. 

Generally, if your puppy starts on the lower end of the weight scale (towards the left side of the chart), then it should stay within this lower range. Likewise, if their birth weight is high, they should stay on the higher end of the scale. 

If you want to find their estimated adult weight, find the corresponding weight and age of your puppy, then follow it down to the bottom to see how big they’ll get! 

Remember that all of these weights are just estimates to give you some general guidance. 

Age Weight in Ounces
Birth 2 ½  2 ¾  3 3 ½  4 4 ¼  4 ½  5 5 ½ 
1 week 3 ¾  4 5 5 ½  6 ½  7 8 9 9 ½ 
2 weeks 5 5 ½  6 ½  7 9 10 11 12 ½  13 ½ 
3 weeks 6 8 9 11 13 14 16 17 ½ 
4 weeks 7 8 9 ½  11 13 15 17 19 ½  21
5 weeks 8 9 11 13 15 17 19 ½  22 24
6 weeks 9 11 12 ½  15 17 ½  20 22 24 27
7 weeks 10 12 14 ½  17 19 ½  22 24 ½  27 30
8 weeks 11 13 16 19 21 ½  24 27 29 33
9 weeks 12 15 17 ¼  20 23 26 29 32 35
10 weeks 13 16 19 22 25 28 31 34 38
11 weeks  14 17  21 24 27 31 34 37 42
12 weeks 15 19 22 26 30 33 37 41 45
13 weeks 16 20 24 28 32 36 40 44 49
14 weeks 17 22 26 30 34 39 43 47 52
15 weeks 18 23 28 32 37 41 46 51 56
16 weeks 19 25 30 34 39 44 49 54 59
17 weeks 20 26 31 36 41 46 51 57 62
18 weeks 21 28 33 37 43 48 54 60 65
19 weeks 22 29 34 39 44 50 56 62 67
20 weeks 23 30 35 41 46 52 58 64 70
21 weeks 24 31 36 42 48 54 60 66 72
22 weeks 25 32 37 43 49 56 62 68 74
23 weeks 26 33 38 44 50 57 64 70 76
24 weeks 26 33 39 45 51 58 65 71 78
25 weeks 27 34 40 46 52 59 66 72 79
26 weeks 27 34 40 47 53 60 67 73 80
Adult (9-12 Months) 2 lbs 2 ½ lbs 3 lbs 3 ½ lbs 4 lbs 4 ½ lbs 5 lbs 5 ½ lbs 6 lbs

Chihuahua Growth and Weight Stages

As puppies grow, they’re not just gaining weight and growing physically – they’re also going through cognitive development and learning how to behave. Their needs will change as they develop. We’ll go through each significant stage and what you can expect. 


Chihuahua Growth & Weight Stages - Age Milestones to Know

Chihuahuas tend to have between two and four puppies in a litter. 

Newborn Chihuahuas are absolutely tiny! They’ll probably be able to fit inside the palm of your hand – how adorable. 

They will only weigh a few ounces. These little pups have no teeth and they can’t see or hear! 

They won’t do much other than sleep and drink milk from their mother. Occasionally you might hear them making little noises when they’re hungry. 

Chihuahua pups have a large surface area to volume ratio, which sounds fancy but just means they have a lot of skin and a very tiny body. This means they lose heat quickly, so it’s really important to keep mother and babies warm. 

1-2 Weeks

Chihuahua Growth & Weight Stages - Age Milestones to Know

In the first two weeks, the puppies will start to grow very quickly. They will likely double their size!

You might notice they wriggle around a bit more, but they will still be completely reliant on their mother. 

2-4 Weeks

Chihuahua Growth & Weight Stages - Age Milestones to Know

This is when things start to get really interesting. They’ll become more active and will begin to open their tiny eyes. Their vision will be blurry at first but will soon clear up. They should be able to hear by about week three or four. 

They will learn to stand and might try to walk (although it may be wobbly). They might even start to show their personalities.

You may see them interacting more with the other puppies, and exploring their environment a bit more.

They’ll make a wider range of noises, especially when communicating with their mother and littermates. 

1-3 Months

Chihuahua Growth & Weight Stages - Age Milestones to Know

Your Chihuahua will continue to grow and gain weight quite quickly during this time.

They will start to explore and walk properly. They’ll be playing and will be very curious about the world around them! You will definitely start to see their personalities at this stage. 

It’s crucial during this time to start to socialize them, by getting them used to sounds, scents, and experiences that are common in any household. You should handle them regularly and start to get them used to grooming. 

They should also be given their first vaccines and parasite treatments during this time. 

The pups will start to develop teeth and may begin to chew on things around them. 

At first, they will still be taking milk from their mother but you can gradually introduce solid foods until they’re fully weaned. 

At two months or older, the puppies will go to their new homes. If you’re adopting or buying a puppy, this is when you’ll pick up your new best friend! 

3-6 Months

Chihuahua Growth & Weight Stages - Age Milestones to Know

At this stage, the puppies will be in their forever homes. By three months old, they will have already gained 30% of their weight!

They will continue to grow at a steady rate. They’ll be eating solid food and should ideally be given three to four small meals a day. 

Teething will continue and reach its peak, so have the chew toys on hand!

During this stage, they should return to the vet for their next set of vaccinations. After that, they can go and explore the outside world! 

This is the time to start training and continue socializing your pup. Get them used to as many experiences, situations, people, and other dogs as possible in a safe way. 

Your puppy should start to be toilet trained and be beginning to get the hang of the rules of the house. 

You should get them used to being groomed and having their teeth brushed. 

They can enjoy walks and playtime, but it’s important not to overdo it. Ensure they get plenty of rest too!

6-9 Months

Chihuahua Growth & Weight Stages - Age Milestones to Know

At this stage, your puppy’s growth will slow down. By nine months, a lot of Chi puppies will have reached their full size. 

By the time they’re seven months old, they should have all of their adult teeth. 

They’ll continue to develop their social skills and learn about the world. You should have some basic training done by now and can start building on that. 

You can begin to take your puppy on more adventures and gradually increase their exercise. 

You can also reduce their meals to twice a day and begin to introduce adult food. I’d recommend waiting until seven months before you do this. 

Their hormones will develop more and they will mature sexually as well as emotionally. You can get your puppy spayed or neutered during this time. 

Your pup should understand the house rules at this point and be reasonably well-behaved (although of course, they’re still babies so they will be playful and mischievous). 

They should be fully toilet trained or certainly well on their way to that goal. 

10-12 Months

Chihuahua Growth & Weight Stages - Age Milestones to Know

By this stage, all Chihuahuas will have reached their adult size and will stop growing. 

They will have fully developed personalities. They should be toilet-trained and well-socialized, and their overall training should be well underway. 

You Have an Adult Chihuahua!

Chihuahua Growth & Weight Stages - Age Milestones to Know

At one year old, you have an adult Chihuahua! You can settle into life with your new best friend and enjoy lots of adventures together. 

As an adult, their weight may fluctuate slightly but it shouldn’t be by much unless there’s a health issue. I recommend weighing your Chihuahua once every few months – my girl gets weighed every six months at her regular vet check. 

After nine or 10 years old, they’re classed as senior dogs. Since Chihuahuas have a longer lifespan than larger dogs, they will hopefully still have a lot of life to live. 

Should You Keep Track of Your Chihuahua’s Weight?

Chihuahuas are lovely little dogs, full of character and a curiosity for life. Although I’m biased, I have to say they’re amazing family members. 

Keeping track of your Chihuahua’s weight helps you to ensure that they’re healthy and enables you to catch any health issues quickly. That way, you and your furbaby can live a long, happy life together!

Chihuahua Growth FAQS

What if your Chihuahua is underweight or overweight?

If you notice your Chi is outside the expected weight range, it’s time to visit the vet to rule out any health issues and determine the problem. 

This is especially important when they’re growing puppies, but still crucial if there are any big weight changes when they’re adults. 

When does a Chihuahua stop growing?

Most Chihuahuas will have reached their adult size between nine and 12 months old. 

What size is a full-grown Chihuahua?

Adult Chihuahuas weigh between two and six pounds and stand between seven and nine inches high. 

When should you spay or neuter your Chihuahua?

Most dogs should be spayed or neutered at around six months of age. It’s best to chat with your vet who can advise you further.