How Big Will My Saint Bernard Get

Bringing home a Saint Bernard puppy means signing up for one of the most dramatic growth curves in the dog world. That armful of puppy will outweigh you in under a year, and almost everything that protects a comfortable adult happens before the growing is finished. This guide gives you the month by month weight picture, the honest timeline for when growth ends, and the daily habits that carry the most weight for a giant breed.

How big will a Saint Bernard get?

A fully grown male Saint Bernard usually weighs 140 to 180 pounds and stands 28 to 30 inches at the shoulder. Females usually weigh 120 to 140 pounds and stand 26 to 28 inches. Saints reach most of their height by around 18 to 24 months, then continue adding chest depth, muscle and head width until roughly two and a half to three years of age.

Genetics, sex, coat type and nutrition all shape the final number, so treat these ranges as a dependable guide rather than a fixed rule. As with every giant breed, how your Saint reaches adult size matters far more than the number it lands on. A Saint who arrives at 170 pounds slowly is in a very different position from one who got there in a hurry.

What makes a Saint Bernard grow the way it does

Saint Bernards were bred as mountain rescue dogs, built for strength and endurance in deep snow rather than speed. That job called for enormous bone, a broad chest and a heavy head, and the modern breed still grows into exactly that outline. The scale of the build is the whole story: there is simply more frame to assemble here than in almost any other breed, and assembling it takes time.

The result is a growth curve that is steep and long at the same time. Through the fastest months a Saint Bernard puppy can add three or four pounds in a single week, which is more than some adult dogs weigh in total. Then, unusually, the growing carries on well past the point where most breeds have finished. Height keeps creeping up toward two years and substance keeps arriving after that, so patience is not just a virtue with this breed, it is the actual plan.

Saint Bernard growth chart, month by month

Use this chart as a friendly guide, not a report card. A Saint tracking a little above or below these numbers while looking lean and moving easily is usually doing just fine.

How Big Will My Saint Bernard Get: reference table

Age	Male weight	Female weight
2 months	25 to 35 lb	20 to 30 lb
3 months	45 to 55 lb	38 to 50 lb
4 months	60 to 75 lb	52 to 65 lb
6 months	90 to 110 lb	75 to 95 lb
9 months	110 to 140 lb	95 to 115 lb
12 months	120 to 155 lb	100 to 125 lb
18 months	135 to 170 lb	110 to 135 lb
2 years plus	140 to 180 lb	120 to 140 lb

When do Saint Bernards stop growing?

Saints reach most of their adult height by around 18 to 24 months, which is already later than most large breeds. After that the change is all about substance. Your Saint broadens through the chest and shoulders, the head fills out, and the last of the adult muscle arrives, usually until two and a half to three years of age.

As a rough guide, a dog with an expected adult weight above 130 pounds keeps developing for roughly 24 to 30 months or more. That is a long runway, and because the frame is being laid down across the whole of it, that window is your prime time to build strong habits around food, movement and joint support.

Why the growth window matters more for a giant breed

During this window your Saint is building the bone, cartilage and connective tissue that will carry a dog heavier than most adults. Growth plates, the soft areas at the ends of the long bones, stay open through much of the first year and well into the second in giant breeds. While they are open, hard impact and excess body weight ask more of a frame that is still forming. With a Saint Bernard the margins are simply thinner than in a smaller dog, because everything the joints carry is scaled up.

How much should a Saint Bernard eat while growing?

Giant breed puppies do best with steady, moderate growth rather than fast growth. With a Saint the temptation to feed for size is strong, and it is the single easiest way to make the growth years harder than they need to be.

• Choose a complete food formulated for large breed puppies, which balances calories, calcium and phosphorus for slower, steadier growth.
• Split the daily amount into three meals while young, then two as an adult, to keep energy even and portions manageable.
• Feed to a lean body condition. You should feel the ribs easily under a light layer of covering.
• Do not add calcium or extra supplements on top of a complete puppy food. Ask your veterinarian before adding anything.
• Confirm the daily amount at every checkup, because with a Saint the correct portion changes faster than you expect.

How to check your Saint body condition in ten seconds

The scale tells you weight, but body condition tells you whether that weight is right for the stage your Saint is in.

• Ribs. Run your hands along the sides. You should feel the ribs easily under a thin layer. If you have to press, ease back on food.
• Waist. Look down from above. You want a clear narrowing behind the ribs rather than a straight barrel.
• Tuck. From the side, the belly should rise toward the back legs rather than hanging level with the chest.

Check every couple of weeks through the growth years and adjust portions gently with your veterinarian guidance.

Growth safe exercise for a Saint Bernard puppy

Saints are calm and willing rather than restless, so the risk is rarely that they run too hard. It is that they carry so much weight through every ordinary movement. Regular, moderate activity on forgiving ground is the goal all the way through the growth window.

• Favour free play, exploring and short walks on grass or dirt over structured distance work.
• Keep long hikes, hard sprints and repeated jumping moderate until well past the second birthday.
• Use a ramp for the car from the very beginning, since jumping down is the harshest movement a giant puppy makes.
• Take walks at the cool ends of the day in summer. A heavy coat and a broad muzzle make Saints tire quickly in heat.
• Let your puppy rest fully between bursts of activity, and note any stiffness the next morning.

Protecting the joints of a giant breed

A Saint Bernard carries more weight through its joints than almost any dog you will meet, and it does so from puppyhood onward. Supporting healthy joint development while that enormous frame is still being built is one of the most useful habits a Saint Bernard parent can have.

Alongside lean feeding and sensible exercise, many big dog parents add a daily joint support chew made for large and giant breeds. MoveGuard Growth is built for exactly this stage. It combines nine actives, including New Zealand Green Lipped Mussel, glucosamine, chondroitin, MSM and hyaluronic acid, to support the developing joints of young large breed dogs across the roughly 8 to 30 month growth window. For a Saint Bernard that window covers virtually the entire growing period, which makes consistency easy to justify. You dose by expected adult weight, so Saints sit at three chews a day. It is made in the USA, holds 90 chews and is backed by a 60 day guarantee.

Signs your Saint Bernard is growing on track

You do not need a weekly weigh in to know things are going well. Look for a bright, settled puppy with a waist you can see from above, ribs you can feel with light pressure, smooth even movement and steady, unhurried gains. A Saint who looks a little lean and rangy through the first year is usually a Saint who is growing exactly as you want.

If you notice limping, stiffness after rest, reluctance to rise or use stairs, or growth that suddenly speeds up, a quick conversation with your veterinarian brings peace of mind and lets you adjust food or activity early.

A simple growth game plan, stage by stage

8 weeks to 4 months. Foundation stage, and the only window where you can still lift your puppy comfortably. A complete large breed puppy food, three calm meals a day, early socialisation, and short bursts of free play on soft ground. Make handling, grooming and the car ramp completely normal now.

4 to 8 months. The steepest part of the curve, when weekly gains are at their largest. Hold the line on lean feeding, keep exercise moderate and rest generous, and put rugs down on any slick floors. This is the natural point to begin a daily joint support routine that carries through the whole window.

8 to 18 months. Height is still creeping up while the chest stays comparatively shallow. Match portions to a lean body condition, since a strong appetite easily outpaces need. Add structured activity gradually and keep favouring soft surfaces over hard ones.

18 months to 3 years. The tall adolescent becomes the broad, powerful adult. Height finishes and substance keeps arriving. Build activity up as your veterinarian advises, and many parents carry a joint support routine straight into adulthood for a dog that will always be moving serious weight.

Common growth mistakes to avoid

• Feeding for size. Trying to grow a bigger Saint faster loads joints that are still forming. The adult size is already written in the genes.
• Skipping large breed puppy food. These formulas control calcium and calories for steady growth. Confirm the right food with your veterinarian.
• Adding calcium supplements. On top of a complete puppy food this can work against balanced development.
• Letting a giant puppy jump down. From cars, beds and sofas. Use a ramp and teach four on the floor early.
• Assuming eighteen months means finished. A Saint is still growing well past that, and the habits need to last as long as the window does.
• Waiting for a problem before supporting joints. The growth window is the ideal time to start, not after signs appear.

The Saint Bernard temperament and the growth years

Saints are famously gentle, patient and steady, which is precisely why the growth years need structure. A calm dog is still a very large dog, and habits that are charming at forty pounds are unmanageable at a hundred and seventy.

Use this time to teach the things that get harder with every month. Calm greetings before your puppy can knock an adult over. Loose leash walking while you can still physically manage a redirect. Comfortable handling for grooming, nail trims and veterinary visits, all established while lifting is still an option. Saints are sensitive and respond far better to short, positive sessions than to firm correction. Puzzle feeders, scent games and gentle obedience work give a young Saint an outlet that does not pound on growing joints. Build the mind and the frame together and you end up with the calm, devoted giant the breed is loved for.

Frequently asked questions

The bottom line

Your Saint Bernard will most likely mature into a 140 to 180 pound male or a 120 to 140 pound female, reaching adult height by around 18 to 24 months and finishing chest and muscle by two and a half to three years. Do not rush any of it. Feed for lean, steady growth, keep exercise sensible and surfaces forgiving while those joints develop, and support the growth window with the right daily habits. That is how you raise a comfortable, confident giant.

Want the simple roadmap in one place? Grab our free Big Dog Growth Guide for the growth window checklist, feeding framework and joint safe exercise limits, all written for large and giant breeds.

This article is for general educational purposes only and is not veterinary advice. It is not intended to diagnose, treat, cure or prevent any disease. Always consult your veterinarian about your dog’s individual health, nutrition and supplement needs. These statements have not been evaluated by the Food and Drug Administration.