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Mouse Age Calculators and Tools

These tools turn your mouse's age into something easier to act on: a human-year equivalent, the life stage it is in now, and a realistic lifespan range. All 2 are free, quick and based on mouse reference data.

Age2 tools

All 2 mouse age tools

Mouse Age tools: what they help with

These tools turn your mouse's age into something easier to act on: a human-year equivalent, the life stage it is in now, and a realistic lifespan range. Life stage decides more than people expect. Food, exercise, how often to see the vet and which health checks are worth asking for all shift as a mouse gets older.

What to know about age and life stage for mice

Mice typically live 1.5 to 3 years. They are mature at around 2 months, so the early months count for a lot of "aging".

Mouse age in human years chart

Human-equivalent age by mouse size, from the same size curves the calculator uses (Small: ; Medium: ; Large: ).
Mouse ageSmallMediumLargeLife stage
3 months444Juvenile
6 months887Adult
1 year151514Adult
1.5 years202018Adult
2 years242422Adult
2.5 years262725Senior
3 years282928Senior

A practical tip

If you adopted your mouse as an adult and only know a rough age, enter your best estimate and use the life stage, not the exact number, to guide care.

Other mouse topics

Mouse care rarely sits in one box. You may also find these useful: mouse behavior tools, mouse breeding tools, mouse cost tools and mouse grooming tools. Or see every mouse tool in one place.

Age tools for other pets

The same kind of tool exists for other species, each using that animal's own reference data: dog age, cat age, rabbit age and hamster age.

Frequently asked questions

Do mice age the same way people do?

No. Most animals age fastest in the first year or two, then slow down. That is why the mouse age calculators use species-specific curves rather than a simple multiplier like "one year equals seven".

How long do mice live?

Typically 1.5–3 years with good care.

Which mouse age tool should I use first?

Most people start with the Mouse Age Calculator, the most used tool in this group. If your question is more specific, the list above describes what each of the 2 tools does.

How accurate are the results?

They are estimates based on published reference data for mice, and each tool lists its sources. Individual animals vary, so treat results as a guide and check health decisions with your vet.