Rat Weights and Life Span

  • Rat Weight

    Things like genetics, being sick, change of food or environment, being a pregnant or nursing doe, or a lack of care, can cause rats to be under these weights, but like us not all rats are the same. Some rats may be heavier than these average weights due to bone structure or overeating.

  • Rat Life Span

    The average healthy happy rat life span is 2-3 years. Although there are stories of rats that have lived closer to 5 years. I have had a male rat that lived to just under 4 years, but he was just a lap rat lol he didn’t move around all that much but loved to snuggle.

Rats' weights and life span can differ due to food, genetics and care. This is a just an average weight and life span guide.

Babies:                                Both                                           Males                                      Females
3 weeks of age               50g – 60g
4 weeks of age               90g – 100g
5 weeks of age                                                                    140g                                          120g
6 weeks of age                                                                    170g                                          150g
7 weeks of age                                                                    220g                                          180g
8 weeks of age                                                                    250g-270g                              200g-250g
Full grown                                                                           300g-500g                              280g-350g