The length of a year on any planet depends on where the planet is orbiting. How long each planet takes to orbit the Sun (in Earth days): see the list
Mercury: 88 days
Venus: 225 days
Earth: 365 days
Mars: 687 days
Jupiter: 4,333 days
Saturn: 10,759 days
Uranus: 30,687 days
Neptune: 60,190 days