Free tools for pet owners and parents — from converting dog years to human years, to predicting your child's adult height.
Convert your dog's age to human years. Accounts for dog size (small, medium, large, giant) using research-backed formulas.
Predict your child's adult height using the mid-parental height formula. See the typical height range based on parent heights.
Track your fertile window and predict ovulation dates for the next 3 cycles based on cycle length.
Calculate your estimated due date from last menstrual period, conception date, or IVF transfer date.
The old "multiply by 7" rule is a myth. Research published in Cell Systems (2020) found that dog aging is non-linear — dogs age very rapidly in their first two years, then slow down significantly. A 1-year-old dog is roughly equivalent to a 15-year-old human; a 2-year-old dog is about 24 in human years. After that, aging slows to roughly 4–5 human years per dog year.
Dog size matters enormously for aging. Small dogs (under 20 lbs) often live 14–16 years and age more slowly after maturity. Giant breeds (over 90 lbs) typically live only 7–10 years and age more rapidly. Our dog age calculator accounts for size using breed-specific data from veterinary research.
Veterinarians classify dogs into five life stages: Puppy (0–1 year), Adolescent (1–3 years), Adult (3–7 years), Mature/Senior (7–10 years), and Geriatric (10+ years). These stages shift based on breed size — a Great Dane is considered senior at 6, while a Chihuahua doesn't enter the senior stage until age 10.
Is the 7-year rule for dog ages accurate?
No — the '1 dog year = 7 human years' formula is an oversimplification. Dogs age extremely fast in their first two years (a 1-year-old dog is roughly 15 in human years), then much more slowly. After age 2, the conversion rate depends on size: small dogs age about 4–5 human years per year, while giant breeds age 6–8 human years per year.
At what age is a dog considered a senior?
It depends on size. Small breeds (under 20 lbs): Senior at 10–12 years. Medium breeds (20–50 lbs): Senior at 8–10 years. Large breeds (50–90 lbs): Senior at 7–8 years. Giant breeds (90+ lbs): Senior at 5–6 years. Vets recommend twice-yearly checkups for senior dogs.
What is the oldest dog ever recorded?
Bobi, a Portuguese Rafeiro do Alentejo, was declared the world's oldest dog at 31 years and 165 days old in 2023, though his age was later disputed. The previously verified record holder was Bluey, an Australian cattle dog who lived to 29 years and 5 months (1910–1939).