Two Chinese zodiac years with the same animal and element are separated by 60 years.
The traditional cycle combines 12 animal signs with five elements: Wood, Fire, Earth, Metal, and Water. Because 12 and 5 are relatively prime, every animal-element combination returns after 12 multiplied by 5, or 60, years.
An animal alone returns every 12 years. For example, Dragon years recur on that shorter interval, but a particular pairing such as Wood Dragon requires the full sexagenary cycle to repeat. This distinction is a common source of confusion in zodiac-year questions.
The 60-year system is known as the sexagenary cycle. It uses combinations of heavenly stems and earthly branches, with the animal signs attached to the branches in popular explanations.