Dog and Cat Age in Human Years Calculator

How to use the Dog and Cat Age in Human Years Calculator

1. Choose dog or cat.
2. Enter your pet’s age in years and extra months.
3. Read the equivalent human age and the age chart.

Example

Worked example

• Dog aged 5: 16 × ln 5 + 31 = 56.8, so about 57 human years (the old rule gives 35)
• Dog aged 10: About 68 human years
• Cat aged 10: 24 + 4 × 8 = 56 human years

Limitations

• The dog formula comes from one breed, the Labrador retriever. Other breeds, especially very large or small ones, age differently.
• The cat figures are a common guide, not a scientific formula.
• Ages under three months are not supported.
• Not veterinary advice.

Sources

• Wang et al. (2020), Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome, Cell Systems

Rates and rules last checked against these sources on 2026-10-08.

About this tool

The old rule of multiplying a dog’s age by seven is not accurate. This calculator uses a formula from a 2020 study of changes in DNA with age in Labrador retrievers: human age ≈ 16 × ln(dog age in years) + 31. For cats it uses the widely used guide of 15 human years at age one, 24 at age two, and four more for every year after that. Dogs of different breeds age at different rates, so treat the result as a fun, rough guide.

Also searched for as: dog years to human years, how old is my dog in human years, cat age in human years, dog age calculator, pet age calculator, is the 7 year rule true.

Dog and Cat Age in Human Years Calculator is part of ToolStack Hub's Calculators. It runs entirely in your browser, which keeps your data private and makes results instant. There is nothing to install and no account to create. There is no usage limit.

Frequently asked questions