Animal Age Calculator

Small Mammal

Mouse age in human years

Enter your Mouse's age to see its human-year equivalent, life stage, and lifespan.

Frequently asked questions

How old is a Mouse in human years?+

Enter your Mouse's age in the calculator above. We use a science-based formula for small mammals — not the old "multiply by seven" rule — and show life stage and lifespan context with your result.

What is the average lifespan of a Mouse?+

Mouses are often cited as living around 2 years on average. Individual animals vary with diet, genetics, and care.

How do I use this Mouse age calculator?+

Pick Mouse (already selected here), enter age in years or use date of birth when available, then calculate. You'll see human-year equivalent, life stage, and how far through a typical lifespan your pet may be.

Mouse age chart

Swipe the table sideways to see all columns.

Mouse age chart
AgeHuman ageLife stage
3 monthsAbout 10Juvenile
6 monthsAbout 20Young Adult
9 monthsAbout 30Adult
1 yearAbout 40Adult
2 yearsAbout 80Senior
3 yearsAbout 120Senior
4 yearsAbout 120Senior
5 yearsAbout 120Senior

This chart is a general estimate. Real aging varies with genetics, weight, health, diet, and veterinary care.