Guinea Pig Weight Calculator
This free guinea pig weight calculator checks whether your guinea pig is a healthy weight for its age and sex — in grams, pounds, ounces or kg. It gives the expected weight by age, a body condition score guide, a weekly weight-change red-flag checker, and a full weight chart with a growth curve.
How the Guinea Pig Weight Calculator Works
| Guinea pig | Healthy weight | In pounds | In kg |
|---|---|---|---|
| Adult female (sow) | 700–1,100 g | 1.5–2.4 lb | 0.7–1.1 kg |
| Adult male (boar) | 900–1,500 g | 2.0–3.3 lb | 0.9–1.5 kg |
| Newborn pup | 60–120 g | 0.13–0.26 lb | 0.06–0.12 kg |
| 3 months | 450–650 g | 1.0–1.4 lb | 0.45–0.65 kg |
Guinea Pig Weight Chart by Age (Male & Female)
The growth curve below shows the healthy weight range from birth to adulthood (the shaded band) with the typical weight through the middle. Guinea pigs grow fastest in the first four to five months, then level off and reach their adult weight by about 12 to 14 months.
Shaded band = healthy range; blue line = typical weight. Before puberty males and females weigh about the same; from around 6 months males pull ahead, reaching 900–1,500 g against a female’s 700–1,100 g.
How Many Kg Should a Guinea Pig Weigh?
A healthy adult guinea pig weighs about 0.7 to 1.5 kg (700–1,500 g). Females (sows) sit at the lower end, around 0.7 to 1.1 kg, and males (boars) at the higher end, around 0.9 to 1.5 kg. In pounds that is roughly 1.5 to 3.3 lb. Anything well below or above that for an adult is worth checking with a body condition score and, if it persists, a vet. Babies weigh far less — just 60 to 120 g at birth — and climb toward the adult range over their first year.
How Big Is a 3 Month Old Guinea Pig?
A 3-month-old guinea pig typically weighs about 450 to 650 g (roughly 1.0 to 1.4 lb) and is still growing fast — it is an adolescent, not yet at its adult weight. At this age it should be gaining steadily week to week. By six months it will usually reach 700 to 1,000 g, and it keeps filling out until about 12 to 14 months. Use the weight-by-age tab above for the expected range at any specific week or month, and remember that frame size varies: a slightly smaller or larger pig that is gaining steadily and scores a 3 on body condition is healthy.
How Do I Check My Guinea Pig’s Weight?
Use a digital kitchen or postal scale that reads in grams. Place a small bowl, a fleece-lined tunnel or an upside-down “pigloo” on the scale and press tare/zero so the container’s weight is cancelled out, then pop your guinea pig inside so it stays still while you read the number. Weigh on the same day each week for a healthy adult (daily for a sick, recovering or senior pig), and write the grams in a log or the weight-change tab above. Tracking the trend is what matters — a single number means little, but a steady drop over a few weigh-ins is an early warning worth acting on.
How Can I Tell If My Guinea Pig Is Over- or Underweight?
Guinea pigs are judged by feel, not a girth formula like farm pigs — there is no reliable tape-measure calculation for them, so pair the scale with a hands-on body condition score (the Size-O-Meter, 1 to 5). Run your hands over the back, ribs and hips: at the ideal score of 3 the ribs can be felt under light pressure, the body makes a smooth oval, and there is no heavy belly sag. If bones stick out sharply the pig is underweight (score 1–2); if you cannot feel the ribs under a layer of fat, or the underbelly nearly drags, it is overweight (score 4–5). A quick guide to weekly weight loss: 1 oz (28 g) is normal, 2 oz means go on alert, 3 oz is a red alert, and 4 oz (113 g) or a sudden drop means see a vet.
Frequently Asked Questions
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