American Guinea Pig Weight Chart

How big do American Guinea Pigs get? See their growth chart and ideal weight.

Quick Answer

The American Guinea Pig is a medium-sized guinea pig that typically weighs 1.5-2.5 lbs. They reach full adult size by approximately 18-24 months. See the complete growth chart and weight milestones below.

Adult Weight Range
1.5-2.5 lbs
Size: Medium

American Guinea Pig Growth Chart

8 weeks
1.5 lbs
12%
3 months
3.8 lbs
30%
6 months
7.5 lbs
60%
9 months
10.0 lbs
80%
12 months
11.3 lbs
90%
18-24 months
12.5 lbs
100%

Is My American Guinea Pig a Healthy Weight?

A healthy American Guinea Pig should have a visible waist when viewed from above, and you should be able to feel (but not see) their ribs. Proper nutrition and regular health checkups are essential for maintaining your American Guinea Pig's ideal weight.

  • Ideal: Ribs easily felt, visible waist, tucked abdomen
  • !Overweight: Ribs hard to feel, no waist visible, rounded belly
  • Underweight: Ribs, spine visible, prominent waist

Frequently Asked Questions

How big does a American Guinea Pig get?

A healthy adult American Guinea Pig typically weighs between 1.5-2.5 lbs. They are considered a Medium breed.

When does a American Guinea Pig stop growing?

Most American Guinea Pigs reach their full adult height and weight by 18-24 months. However, they may continue to "fill out" with muscle for a few months after.

How much should a American Guinea Pig puppy weigh at 3 months?

At 3 months old, a typical American Guinea Pig puppy weighs approximately 3.8 lbs. Growth rates vary, so consult your vet if concerned.

How can I tell if my American Guinea Pig is overweight?

A healthy American Guinea Pig should have a visible waist when viewed from above, and you should be able to feel (but not see) their ribs through a thin layer of fat. If the waist isn't visible, ribs are hard to feel, or the belly sags, your American Guinea Pig may be overweight. Consult your vet for an accurate body condition assessment.

Official Breed Standards

For official American Guinea Pig size and weight standards, refer to the AKC Breed Standards. Breed standards define the ideal size range, but individual guinea pigs may vary based on genetics, diet, and overall health.

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American Guinea Pig Weight Chart 2026 | Size, Growth & Ideal Weight | Clawmate