Newborn puppy weight gain: how much is normal, and when to call the vet
Updated October 31, 2026 · 2 min read · by the PupCurve editorial team
In the first two weeks, the scale tells you things you can't see. A newborn that isn't gaining weight is often in trouble before it looks it. A daily weigh-in is the cheapest early warning a breeder has.
What normal looks like
The Merck Veterinary Manual says neonates should gain weight steadily from the first day, and that normal weight gain is 5 to 10% of body weight a day. A transient mild loss of up to 10% of birth weight on day one is described as acceptable.
Merck also gives a rule of thumb by size: puppies should gain about 1 to 3 g a day per kg of anticipated adult weight. For a dog that will weigh 25 kg, that's roughly 25 to 75 g a day. Birth weight and the breed's expected adult weight are the two things to know.
How to weigh
- Use a digital scale that reads in grams. A kitchen scale and a shallow bowl work fine.
- Weigh at roughly the same time each day.
- Mark each puppy: coloured collars or ties, or a dab of non-toxic paint on the coat, so records stay straight.
- Write the weights down at the time. The Merck manual says to record weights daily for the first two weeks, then every three days until a month old.
The Litter Pass has a sheet for this: enter every pup's weight once a day, and each one gets a percent change, a chart and a warning if it loses weight.
What to do about a dip
A small drop on the first day isn't automatically a worry, but watch it closely and weigh again that evening. After day one, a puppy that loses weight, or doesn't gain for a day, should be looked at. Merck lists a decrease in weight gain among the clinical signs of neonatal sepsis, a fast-moving bacterial infection, and neonatal mortality of 9% to 26% has been reported, highest in the first week. A stalled scale is often the first thing you can measure.
Call your vet the same day if a puppy loses weight after day one, has weak or no suckling, feels cold, is limp, cries constantly, or is pushed away from the others. Don't wait to see if it improves. Newborns have little body fat and very little glucose reserve, and they can go downhill within hours.
Low birth weight
Puppies born much lighter than the rest of the litter are at higher risk. Merck lists low birth weight, under 350 g for a medium-size breed, as one factor that predisposes a newborn to sepsis, along with chilling and a difficult delivery. Weigh these puppies more closely and talk to your vet about a plan for them at the first check.
After two weeks
Once the daily check settles into a pattern, you can weigh every few days, and then weekly from about a month. Growth then follows the curve you can see on the puppy growth calculator, which becomes useful from 8 weeks.
Questions people ask
How much weight should a newborn puppy gain per day?
About 5 to 10% of its body weight a day, according to the Merck Veterinary Manual.
Is it normal for a newborn puppy to lose weight?
A small loss of up to 10% of birth weight on day one can happen. After that, any loss, or a day without gain, is a reason to call the vet.
How often should I weigh newborn puppies?
Daily for the first two weeks, then every three days until a month old, according to Merck.
What if one puppy is much smaller than the others?
Low-birth-weight puppies are at higher risk. Weigh them more closely and talk to your vet about feeding and warmth.
Sources
This guide is general information, not veterinary advice. If you're worried about a puppy, call your vet. In an emergency, go to the nearest emergency clinic.