Age CalculatorYTScript

Dog Age Calculator

Enter your dog’s birthday or the years already lived, pick a size group, and see a rough equivalent in human years. This is an estimate, not a veterinary opinion.

Runs in your browser — dates never leave this device
How do you want to enter age?
Date of birth
Age at the date of

Toy and small use the same published column (about 20 lb / 9 kg or less). Medium is about 21–50 lb, large 51–90 lb, giant over 90 lb.

Age will show up here Enter a date of birth. You can change the “age at” date if you want a day other than today.

How to use it

  1. 1

    Choose a size group. Toy and small share one published column; medium, large, and giant use their own.

  2. 2

    Enter a birthday, or the years and months already lived.

  3. 3

    Read the estimate, the disclaimer, and the ×7 contrast figure — ×7 is not the default.

How this calculator counts age

A widely repeated rule of “one dog year equals seven human years” is a rough myth. Dogs mature quickly in the first two years, and larger dogs often age faster later on.

The default numbers on this page follow a common public guideline summarized by the American Kennel Club from the American Veterinary Medical Association for a medium-sized dog: about 15 human years in the first year, about 9 more in the second (24 in total), then about 5 each year after. After year two, the size columns use the comparative chart reprinted on the 2019 AAHA canine and feline age poster, which credits Appendix B of Dog Owner’s Home Veterinary Handbook.

Toy and small dogs use the ≤20 lb (about 9 kg) column, medium 21–50 lb, large 51–90 lb, and giant over 90 lb. Breed names are not a separate table — if you are unsure, pick the group that best matches adult weight.

Other date tools

Age calculatorExact age in years, months, and daysChronological age calculatorAge on an assessment date, with Y;M;D copyBaby age calculatorWeeks, calendar months, and days after birthCat age calculatorAn estimate in human years from a public chartDays between datesCount days, with or without the end dateAdd or subtract daysMove a date by years, months, weeks, or daysDay of the week calculatorWeekday, day of year, and ISO week

Questions

What formula do you use?

Year 1 is counted as 15 human years and year 2 adds 9, matching the AVMA medium-dog guideline as described by the AKC. From year 3 onward we interpolate the size-specific figures in the 2019 AAHA age poster (adapted from Dog Owner’s Home Veterinary Handbook, Appendix B). Part years are interpolated between whole-year rows.

Why isn’t ×7 the answer?

It is a long-standing shortcut, but it understates the first two years and ignores size. We show that number only as a contrast, labelled as a common myth.

Does this tell me how long my dog will live?

No. It is a rough comparison in human years, not a diagnosis, a health score, or a lifespan promise. A veterinarian who knows your dog can say much more.