ToolsConductScience tool
Mouse Colony ManagementFree in-browser calculator

Mouse Age Converter.

Convert mouse age to human-equivalent age using Dutta & Sengupta (2016) piecewise scaling. Strain-specific lifespan factors, life-stage classification, and a one-click CSV export for methods sections.

PrivateData stays in your browser
LiveNo sign-up required
Open methodFormula shown on this page
CitableMethods and citation included

Calculator

Results update in place

Try it out

Load example mouse age converter data to see the full workflow

Need cross-species comparison? Try the universal Animal Age Converter

Mouse Age

Conversion

Mouse age
126 d
18.0 wk · 4.1 mo
Human-equivalent
28 human years
Dutta & Sengupta (2016)
Life stage
Young adult (6 wk–6 mo)
Strain C57BL/6J
Lifespan position
16%
of strain median

Position on Strain Lifespan

NeonatalPre-weaningJuvenileYoung adultMature adultMiddle-agedSenescentMedian

When to use

  • Labeling cohort age in human-equivalent terms for translational papers
  • Choosing the right developmental window for a juvenile or adolescent study
  • Comparing aging-study cohorts across labs that use different age conventions
  • Justifying cohort age in IACUC and grant applications
  • Communicating cohort age to clinical collaborators or PR/comms teams

Do not use for

  • As a biological-age estimate — use epigenetic clocks (Horvath, GrimAge) for that
  • For non-mouse species — use the Lab Animal Age Converter for rat and zebrafish
  • For genetically-modified strains with altered lifespan (e.g. progeroid models) — the published scaling does not apply

Days 1–42 are non-linear, even by mouse standards

Mice complete sexual maturation by 6 weeks. The 150-day-per-day ratio reflects this compressed development — never linearly extrapolate from a single time point during this window.

Strain lifespan factors do not change human-age math

A 12-month BALB/cByJ mouse has the same human-equivalent age as a 12-month C57BL/6J mouse — the strain factor only adjusts where each mouse sits on its own lifespan curve, not the absolute human-age conversion.

Aging studies should report both age and human-equivalent

Reviewers increasingly expect the human-equivalent age in figure legends. The calculator gives you a one-click value to drop into Methods.

Beyond 36 months you are off-curve

No published scaling applies past ~36 months for B6, and strains with <24 month median lifespan plateau even earlier. The calculator flags this explicitly.

1

Method

Mouse age (days) is converted to human-equivalent days via a piecewise function: 150× from day 1 to 42, 45× from day 42 to 180, 30× from day 180 to 365, 25× from day 365 to 730, and 20× thereafter. Lifespan position = mouse_days / (median_B6_days ×\times strain_factor). Strain factors are taken from NIA Aging Mouse Phenotyping Center medians.

2

Published

Published 2026-04-06. Calculations support planning and documentation; verify procurement decisions against manufacturer specifications or institutional SOPs.

3

How to cite

How to Cite

ConductScience Mouse Age Converter. ConductScience, Inc. 2026. Available at: https://conductscience.com/tools/mouse-age-converter

Dutta S, Sengupta P. Men and mice: Relating their ages. Life Sciences. 2016;152:244-248.

Flurkey K, Currer JM, Harrison DE. Mouse models in aging research. In: The Mouse in Biomedical Research, 2nd ed. Academic Press; 2007.

Dutta & Sengupta (2016) Mouse-Human Age Scaling

The piecewise model used by the calculator:

  • Days 1–21 (pre-weaning): ~150 human days per mouse day
  • Days 21–42 (juvenile, weeks 3–6): ~150 human days per mouse day
  • Days 42–180 (young/mature adult, months 1.5–6): ~45 human days per mouse day
  • Days 180–365 (middle age, months 6–12): ~30 human days per mouse day
  • Days 365–730 (aged, months 12–24): ~25 human days per mouse day
  • Days >730 (senescent): ~20 human days per mouse day

The published model anchors mouse adulthood (~3 months) to human age 20, mouse middle age (~12 months) to human age 38, and mouse senescence (~24 months) to human age 60 — the calculator reproduces these landmarks exactly.

Why Age Matters in Translational Studies

Most preclinical studies use 8–12 week old mice, which corresponds to a human age of ~18–22 — a window almost no human disease cohort represents. This is one of the reasons preclinical-to-clinical translation often fails for aging-related conditions.

For aging research, the recommended cohorts are:

  • Young adult: 3–6 months (~22–34 human years)
  • Middle-aged: 12–14 months (~38–47 human years)
  • Aged: 18–24 months (~56–69 human years)

Use this calculator to label your cohorts in human-equivalent terms when writing methods sections — it dramatically improves clinical reviewers' interpretation.

Frequently asked

325
Free tools
1,200+
Institutions
100%
Client-side
0
Uploads required