Dog Age Calculator
Convert your dog’s age to human years. Free calculator by breed size (small, medium, large, giant) with life stage and care tips.
Dog Age Calculator
How old is your dog?
Breed size
How Dog Age Calculation Works
- First year ≈ 15 human years
- Second year ≈ 9 human years
- Each year after ≈ 4–7 human years (by size: small 4, medium 5, large 6, giant 7)
This dog age calculator converts your dog's age to human years using breed size (small, medium, large, giant). Get a human age equivalent, life stage, and care recommendations so you can plan vet visits, diet, and exercise. Free dog years to human years converter by breed size.
How to Use Dog Age Calculator
How to enter your dog's age
Type your dog's age in years (e.g. 5 or 5.5). Use decimals for months (e.g. 0.5 for 6 months). The dog age calculator accepts ages from 0 to about 30 years.
Select breed size
Choose Small (under 25 lbs), Medium (25–60 lbs), Large (60–90 lbs), or Giant (over 90 lbs). Size affects how fast dogs age: smaller breeds tend to age slower than larger ones.
What to do with your results
See the human age equivalent, life stage (e.g. Puppy/Young Adult, Adult, Mature Adult, Senior), and brief care recommendations. Use this to tailor diet, exercise, and vet frequency.
Calculator Features
Human years by breed size
Converts dog years to human years using size-based rates: small 4, medium 5, large 6, giant 7 human years per year after age 2.
Life stage labels
Shows whether your dog is in the puppy, adult, mature, or senior stage so you can adjust care and watch for age-related changes.
Care recommendations
Short, practical tips for each life stage to support health and wellbeing.
Simple and free
No sign-up required. Enter age and size to get an estimate in seconds.
Complete Function List
- Dog age to human years conversion:
- Breed size selection (small, medium, large, giant):
- Life stage (Puppy/Young Adult, Adult, Mature Adult, Senior):
- Care recommendations by stage:
- First year ≈ 15 human years, second year ≈ 9:
- Years after 2 scaled by size (4–7 human years per dog year):
- Ages 0–30 supported:
- Free, no account needed:
Common Calculations & Examples
Example 1: 5-year-old medium dog
Problem: You have a 5-year-old medium-sized dog (e.g. 40 lbs) and want to know how old they are in human years.
Steps:
- Enter 5 in the dog's age field
- Select Medium (25–60 lbs)
- View results
Explanation: Medium dogs add about 5 human years per year after age 2, so 2 years = 24, then 3 more years = 15, total ~39–45 depending on exact formula.
Example 2: 1-year-old puppy
Problem: Your puppy just turned 1. How old is that in human years?
Steps:
- Enter 1 in the dog's age field
- Select the breed size that will apply as they grow
- View results
Explanation: The first year is treated as about 15 human years in most modern dog age formulas.
Example 3: Senior large dog
Problem: Your large dog is 10. You want a human age equivalent and life stage.
Steps:
- Enter 10 in the dog's age field
- Select Large (60–90 lbs)
- View results
Explanation: Large dogs age faster (about 6 human years per year after 2), so they reach “senior” human equivalents sooner.