Puppy Weight Calculator

What this puppy calculator checks that the other ones do not

The other puppy pages work in one direction: they take what you can see today and project the grown dog. This page runs the other way. You start from the adult weight you expect, and it tells you what a puppy of that size should weigh now, how fast it should be gaining over the coming weeks, and whether the number on your scale sits inside or outside that band.

That makes it the middle step between estimating a size and feeding for it. Once you know the expected weight for this month, the amounts on the food bag stop being a guess, and a weight outside the band shows up within a week.

Everything here is in months, because the published growth charts are month based. Type the weight in pounds or kilograms and the calculator converts both ways.

The share of adult weight a puppy reaches at each month age

The model rests on one idea: at a given age, a puppy of a given size class has reached a fairly predictable share of its adult weight. The American Kennel Club publishes those shares for four size classes, and its puppy growth chart, updated in June 2026, is the source for every anchor in this calculator.

Two honest limits sit behind that table. First, AKC publishes nothing below 6 months, so the calculator fits a straight line from the 6 month anchor back to a 2 month point of 30, 27, 23 and 20 percent. Anything under 4 months is a rough guide, because the spread between puppies is wider than the difference between classes. Second, ages between anchors are interpolated in a straight line, which smooths over real growth spurts.

The percentages describe timing, not an ideal weight. A puppy that reaches 75 percent of adult weight at 6 months is not a better grown dog than one at 65 percent, and AKC says as much on the chart itself. For a peer reviewed take on the same idea, the growth standard charts published by Salt and colleagues in 2017 in PLOS ONE were built from more than 6 million healthy dogs seen at a large network of primary care veterinary hospitals in the United States, covering the same stretch from 12 weeks to 2 years.

Worked example: a 4 month old puppy at 22 lb heading for 50 lb

Take a medium breed puppy, 4 months old, weighing 22 lb, with an expected adult weight of 50 lb. At 4 months the medium column sits between the 2 month and 6 month anchors, and the interpolation gives 46.5 percent.

Reading the rows in order: the puppy should weigh about 23.3 lb and weighs 22 lb, which is 5 percent under the midpoint and inside the band. Read the other way, 22 lb implies a 47.3 lb adult, close to the 50 lb target and a good sign that the target is realistic. Over the coming month the share should climb from 46.5 to 56.25 percent, which is 4.9 lb for this puppy, or about 1.1 lb a week.

If the adult target is left at 0, the calculator uses the class range instead: a medium breed runs 21 to 50 lb, so the expected band widens to 8.8 to 25.6 lb. That is honest but not useful, which is why a known adult weight, from the parents or the breed standard, sharpens every row.

Weekly gain targets by month and size class

For a feeding plan the most useful output is the pace, not the weight itself. The table shows the target weekly gain for the coming month, from the same chart with four example adult weights: a 12 lb small breed, a 40 lb medium, a 70 lb large and a 130 lb giant.

A weekly gain of a few tenths of a pound is normal for a small breed and easy to miss on a bathroom scale, which is why a kitchen scale earns its keep. The month to month drop matters too: the 40 lb medium puppy that gains 0.9 lb a week at 4 months should gain 0.6 at 6 months and 0.3 at 9 months. A gain that holds steady while the chart expects it to slow means overfeeding.

These are targets for a puppy in lean body condition, and the calculator reports the coming month rather than a fixed number, because the pace changes as the curve flattens.

Why large and giant puppies slow down after about 8 months

Large and giant breed puppies look undergrown next to small breed littermates of the same age, and the chart says they are not behind. They start lower and stretch the same journey over more months. The table shows pounds per month for a 70 lb large breed and a 130 lb giant.

From 2 to 6 months the large breed puppy gains about 6.5 lb every month. From 8 months on that pace falls to about 3.5 lb a month, and from 9 months it drops again to about 2.3 lb a month. The giant breed holds its pace longer, but the same shape is there: 9.8 lb a month early, 6.5 lb a month through the middle of the first year, 4.3 lb a month from 12 to 18 months. Weight gain slows through the second half of the first year for both.

AKC's chart makes the same point in percentages: large breeds are still at 85 percent of adult weight at 12 months and giant breeds at 80 percent, with the last 15 to 20 percent arriving between 12 and 24 months. The growth standard charts from Salt and colleagues (2017) show the same flattening from mid year onward, which is why their curves run to 2 years for the biggest dogs. Bone development, not weight, finishes last in a giant breed.

Reading the verdict: growing too fast, on track, or too light

The verdict line compares the weight you typed against the expected midpoint and speaks in three bands. Inside 15 percent of the midpoint is on track. More than 15 percent above reads as heavier than the chart expects, and more than 15 percent below reads as lighter. The band is deliberately wide, because breed, sex and body condition move real puppies several pounds either way.

Heavier is the side worth taking seriously for large and giant breeds. Fast weight gain in a growing large breed puppy loads joints still forming, and the WSAVA nutrition guidance is blunt about it: large breed puppies should be fed in a portion controlled way for a slow rate of gain, with a body condition score near 4 out of 9 rather than 5, to avoid joint and skeletal problems tied to fast growth. A puppy riding the top of the band for two weigh ins in a row is a feeding adjustment, not a crisis.

Lighter than expected usually means the feeding plan has fallen behind the growth, or the adult target is too big for the puppy in front of you. Check the implied adult weight line: if a 50 lb puppy at 5 months implies an 89 lb adult and you expected 60 lb, the size class was wrong, not the puppy.

None of this is a diagnosis. The verdict is a screening flag built on population averages, and a veterinarian reading the same numbers with a body condition score can tell you which flag to ignore.

How to weigh a puppy so the numbers mean something

The chart only works as well as the number you feed it. Weigh on the same scale each time, because household scales disagree with each other by a pound or more. Weigh at the same time of day, morning before breakfast is cleanest, since a puppy can carry half a pound of water and meals by evening. Weigh weekly during growth and write it down, because the trend matters more than any single reading.

Small puppies are hard to hold still on a floor scale, so stand on the bathroom scale holding the puppy and subtract your own weight. A kitchen scale handles the first months of a small breed. The same method weekly keeps gain comparable.

Weight is only half the picture. The body condition score charts from the WSAVA Global Nutrition Toolkit, published alongside its 2011 nutrition guidelines, describe what a puppy at 4 to 5 out of 9 should look like: ribs you can feel under a thin cover, a waist visible from above and a tuck behind the ribs from the side. A puppy can sit inside the expected weight band and still carry too much fat, and the score catches what the scale misses.

When the estimate is wrong, and when to call the vet

Three things push a real puppy off a population chart. Genetics first: a mixed breed puppy with known parents leans toward them, and a purebred leans toward the breed standard rather than the class midpoint. Sex second: males of most breeds run heavier than females. Neutering third: the 2017 growth standard study found that neutering before 37 weeks shifts the growth curve up slightly, a small shift next to the spread between dogs.

The calculator flags one case on its own: when the implied adult weight lands far outside the class range, the size class was probably picked wrong, and every row downstream inherits that error. Fix the class before worrying about the weight.

Call the vet when the trend breaks rather than when a single reading looks odd. A puppy that stops gaining for two weeks in a row, loses weight, eats without gaining, or carries a rounded belly with visible ribs is showing signs no chart explains, and so is a large breed puppy that jumps two band widths in a month. Bring the written weights; a veterinarian cannot reconstruct that record later.

This page is a growth estimating tool, not veterinary advice. Breed differences, body condition and health history all move the numbers, and a puppy that looks well and eats well matters more than a chart does.