Mouse To Human Age Calculator

Reviewed By: Patrick Myers (BSME)

Enter either the mouse age or the human age into the calculator to determine the equivalent age in the other species.

Mouse → Human

Human → Mouse

DOB → Age

Notes: There is no single universally accepted mouse↔human age conversion. Choose a model that fits your use case. “JAX Life‑stage” uses commonly cited adult-aging anchors (for example, about 10–15 months is roughly human 38–47; about 18–24 months is roughly 56–69). “Simplified 3‑point” is a rough interpolation (for example, about 60 days is roughly human ~16; about 1 mouse year is roughly human ~42; about 2 mouse years is roughly human ~70). “Legacy” is a simple linear internet formula and is included for comparison only.

Related Calculators

Mouse to Human Age Formula

There is no single universally accepted mouse-to-human age conversion. Mice mature very rapidly early in life and then age more slowly, so a simple one-line linear formula can be misleading. A common approach is to use anchor points (life-stage milestones) and estimate ages in between with linear interpolation.

H \approx \operatorname{interp}\!\left(M_d;\,[0,60,300,450,540,730],\,[0,16,38,47,56,69]\right) M_d \approx \operatorname{interp}\!\left(H;\,[0,16,38,47,56,69],\,[0,60,300,450,540,730]\right)

Variables:

H is the estimated human age in years
M_d is the mouse age in days (postnatal)

To estimate the human age equivalent of a mouse’s age, first convert the mouse age to days (for example, years × 365). Then find the two nearest anchor points around that age and linearly interpolate between their human-age values. To estimate mouse age from a human age, do the same interpolation in reverse (human years → mouse days).

Mouse Years to Human Years Conversion Table (JAX Life‑stage interpolation)
Mouse Age (years)	Human Age (years, approx.)
¼	18.9
½	27.2
¾	35.6
1	41.9
1¼	47.6
1½	56.5
1¾	62.8
2	69.0
2¼	75.2
2½	81.5
2¾	87.7
3	94.0
Model used: JAX Life‑stage style linear interpolation between anchor points (mouse days → human years): (0,0), (60,16), (300,38), (450,47), (540,56), (730,69). Values beyond ~2 years are extrapolated and are highly approximate.

What is a Mouse to Human Age Calculator?

A Mouse to Human Age Calculator is a tool that estimates the equivalent age between mice and humans. This can be useful in research and in pet care, but results are always approximate because the relationship is not a single fixed conversion. Most calculators use a model based on life-stage anchors (milestones) and interpolate between them to reflect that mice mature quickly early on and then age differently later in life.

How to Calculate Mouse to Human Age?

The following steps outline how to calculate the Mouse to Human Age.

Determine the mouse age.
Convert the mouse age to days (for example, mouse years × 365).
Choose a model (for example, a JAX life‑stage anchor-point model).
Linearly interpolate between the two nearest anchor points to estimate the equivalent human age.
Check your answer with the calculator above (and remember it is an estimate).

Example Problem :

Use the following variables as an example problem to test your knowledge.

Mouse Age (M) = 2 years (≈ 730 days)

Human Age (H) ≈ 69 years (JAX life‑stage model)