Here's recent article on the subject.
For a quick calculation:
For first two years:
- 12.5 years per human year for the first two years for small dogs
- 10.5 years per human year for the first two years for medium-sized dogs
- 9 years per human year for the first two years for large dogs
For years 3+:
- Small: Dachshund (Miniature) 4.32, Border Terrier 4.47, Lhasa Apso 4.49, Shih Tzu 4.78, Whippet Medium 5.30, Chihuahua 4.87, West Highland White Terrier 4.96, Beagle 5.20, Miniature Schnauzer 5.46, Spaniel (Cocker) 5.55, Cavalier King Charles 5.77, Pug 5.95, French Bulldog 7.65
- Medium: Spaniel 5.46, Retriever (Labrador) 5.74, Golden Retriever 5.74, Staffordshire Bull Terrier 5.33, Bulldog 13.42
- Large: German Shepherd 7.84, Boxer 8.90
And if you want to check how old you are in dog years in the breed(s) of your choice, check here!