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How big will my puppy get?

Puppies don’t grow at a steady pace in their first year: fast at first, then slower and slower. The growth curve shows how much of its adult weight a puppy has already reached.

The short answer

According to the growth curves in the FEDIAF guidelines, a puppy weighs about 32–51% of its adult weight at 3 months and 57–77% at 6 months, depending on size. Small dogs are fully grown at about 12 months; giant breeds are only at about 82% by then. Divide the weight by the share for a rough adult weight: 13 lb at 3 months ÷ 0.46 = about 28 lb.

Share of adult weight by age

The chart shows what percentage of its adult weight a puppy typically weighs at each age. The columns depend on how heavy the dog will be as an adult.

AgeUp to 15 lb15–33 lb33–61 lb61–105 lbOver 105 lb
2 months36%31%25%24%17%
3 months51%46%42%39%32%
4 months62%57%53%49%42%
5 months70%65%62%58%50%
6 months77%72%69%64%57%
9 months92%87%85%79%72%
12 months100%97%97%90%82%

Calculated with the growth curves in the FEDIAF guidelines (2025), based on GfE 1989 and Meyer & Zentek 1992. They apply from 8 weeks to 1 year. The weight classes are set in kg: up to 7, 15, 27.5 and 47.5 kg.

How to estimate adult weight

  • Weigh your puppy and note its age.
  • Find the column it probably falls into. For purebred dogs, the breed’s typical weight helps.
  • Divide the weight by the share in the chart.
  • If the result doesn’t fit the column, use the next larger one.

Example: a mixed-breed puppy weighs 13 lb at 3 months. The 15–33 lb column says 46%: 13 ÷ 0.46 = about 28 lb. That fits the column, so 28 lb is a good rough guide. The puppy food calculator estimates it for you.

How accurate is it?

The curves describe a typical pattern. Every puppy grows a little differently, and mixed breeds often fall between two columns. Treat the result as a rough guide, not a prediction.

Weigh your puppy regularly. The Merck Veterinary Manual advises tracking weight gain weekly. The nutritionists at Tufts University say at least monthly until 6 months.

When is a dog fully grown?

According to the Merck Veterinary Manual, small and medium dogs may be fully grown at 8–12 months, large and giant breeds often only at 10–16 months. Some giant dogs take almost 2 years.

Slow beats fast

Too much food speeds up growth (FEDIAF, Merck). Especially in large breeds, that can harm the skeleton. Keep your puppy lean: ribs easy to feel, waist visible from above.

Questions

How big will my puppy get?

Divide its weight by the share of adult weight in the chart. A puppy that weighs 13 lb at 3 months and belongs to the 15–33 lb group will weigh about 28 lb. That’s a rough guide.

When does a puppy reach half its adult weight?

According to the growth curves in the FEDIAF guidelines, small dogs at almost 3 months, medium dogs at 3 to 4 months and giant breeds only at about 5 months.

My puppy weighs more than the chart says. Is it overweight?

Not necessarily; it may just grow bigger. Check its shape: ribs easy to feel, waist visible from above. But according to the FEDIAF guidelines, too much food doesn’t always show in a puppy’s shape. If it grows clearly faster than the curve, especially in large breeds, talk to your vet.

Sources

Last checked: October 2026