How old is my Lab in human years?

Short answer

A 2020 study of 104 Labrador Retrievers in Cell Systems matched dog and human DNA-methylation aging and proposed human age ≈ 16 × ln(dog age) + 31. By that formula a 1-year-old Lab is about 31, a 4-year-old about 53, and a 12-year-old about 71. It’s an estimate, not a diagnosis.