Quick answer: A dog's age in human years isn't simply ×7. This calculator shows the traditional method side by side with the 2019 UCSD epigenetic formula (human age = 16 × ln(dog age) + 31), based on DNA methylation research.
Last reviewed: September 2026
Key facts
- The ×7 rule is a myth; dogs age faster early, slower later.
- UCSD formula: human age = 16 × ln(dog age) + 31.
- Based on DNA methylation clocks (2019 research).
- Size matters: small breeds live longer than giant breeds.
Free dog age calculator: traditional vs science-based UCSD formula side by side.
How to use
- Enter your dog's age in years.
- Compare traditional ×7 vs UCSD formula.
The formulas
Traditional: human = dog × 7
UCSD (2019): human = 16 × ln(dog) + 31
Worked examples
1-year-old dog: Traditional = 7. UCSD = 16×ln(1)+31 = 31. A 1-year dog is like a 31-year human!
5-year-old dog: Traditional = 35. UCSD = 16×1.609+31 = 56.7.
10-year-old dog: Traditional = 70. UCSD = 16×2.303+31 = 67.8.
Frequently asked questions
Is ×7 accurate?
No. Dogs mature fast in year 1 (like 31 human years), then slow down.
What is the UCSD formula?
human = 16 × ln(dog age) + 31, from DNA methylation research (2019).
Do small dogs live longer?
Yes. Small breeds often reach 15+ years; giant breeds 8-10.
Why do dogs age faster?
Higher metabolic rate and faster cellular aging, especially early.
When is a dog senior?
Small: ~10 years. Large: ~7 years. Giant: ~5-6 years.
Can I slow aging?
Healthy weight, exercise, vet care, and good diet help.
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